The Admissibility of Expert Evidence in Criminal Proceedings

Rabelais’ Judge Bridlegoose lays down a challenge for the legal profession. Bridlegoose threw dice to decide cases his deductive logic being that by using dice both sides had an equal chance of winning and therefore over the long run he would get the ‘right’ result in about half the cases . A number that given the “arbitrary confusion, the obfuscation and chicaneries of lawyers and the possibilities of his own fallibility there was no such guarantee he would achieve this level” . All serious theoretical discourse on the Law of Evidence mandates ‘rectitude of decision’ so the challenge is to get a better rectitude of decision in both design and practice than would be achieved by throwing dice. The scandals in recent years surrounding the cases of people such as Angela Canning and Sally Clarke and the overturning of convictions based on expert medical evidence have exemplified a classic example of a failure to get rectitude of decision; if their judgement had been based on the roll of a dice their results may have been fairer to them. The issue of expert evidence and its relationship to the exclusionary evidential rules on opinion and hearsay has been the subject of a large academic scrutiny and it is to this subject matter that this work will be focused upon.

The dangers of expert evidence are well rehearsed in the courts and it is a very contentious area, the well known dicta of Lawton LJ in the case of R v. Turner exemplifies an ancillary point to the one made above, veracity is to be determined by the decision maker and we must become wary of abrogating such a right and stated that English law had to be wary of becoming too deferential or reliant on expert evidence because it is trial by judge and jury not by expert. The issues which this work seeks to deal with can be of the utmost importance, in this work I hope to critically assess the current state of the law as regards expert evidence post-Criminal Justice Act 2003 . The work attempts to fuse the two themes that I have implied here namely; the current attitude to expert evidence vis a vis the inherent conceptual dangers of the subject matter and secondly, whether as a whole it deals with the aims of the Law of Evidence more generally. Its position as an exception to such a large rule as Hearsay makes this Janus-like approach necessary and lends considerably more conceptual clarity in a subject area which is contentious for various reasons with rich intellectual backgrounds.

We will start by looking at a history of the evolution of the concept of expert evidence as an exception to the exclusionary rule against opinion evidence which will combine both elements of practical law and theoretical background justifications for the existence of such laws. This section will be the bulk of the essay as we seek to build an in depth account of Expert Evidence and will look at a number of issues such as the courts attitude to new technologies and the detailed case law about the areas upon which the courts will allow expert evidence, always evaluating this against the background purposes of the rule. The evaluation in this section attempts to assess whether the rules on expert evidence exhibit a holistic coherence. This neatly flows into the second part of the work which will discuss expert evidence as an exception to the hearsay rule. In conclusion, I will draw both strands of the work together and propose a number of tentative amendments, however whilst this is a critical work, as we shall see the complicated nature of all the issues requires us to go into great detail about a large number of issues. The nature of this work is about criticising the lack of holistic treatment of the subject matter rather than substantive reforms.

Philosophy of Expert Evidence

The jurisprudential treatment of the law of evidence has a long history and it would be impossible in this section to do justice to the variety and complexity of the jurisprudential arguments that surround this subject matter. However as we shall see Expert Evidence is a particularly interesting subject because of its position in the Law of Evidence.

The general law of evidence in the Anglo-American system is built on a system of free proof with a number of exclusionary rules. This picture is very neat and easy for us to deal with on a conceptual basis. There is a clear need for any decision-maker to have all the available facts before him so that he can make the correct, or just, decision. However, some evidence is inherently misleading, unreliable and prejudicial. The individual rights of the parties and the demands of justice in the Anglo-American system mean that this evidence is excluded so that in effect the decision-maker makes his deliberations on all the ‘best evidence’ available at the time. The Adversarial trial system is the best way of eliciting this information from the available sources such as witnesses and real evidence. This is the prosaic understanding that underlies to a large degree the modern day criminal justice system.

However, the situation becomes more difficult when evidence doesn’t neatly fall into the reliable / unreliable category. Furthermore it can cause confusion where generally unreliable evidence is admitted in certain cases because of unique concerns. Expert Evidence is precisely one of these types. We will discuss these issues in greater detail below however we will give a brief overview at this point. The reasons for including expert evidence are self-evident to a point, it is a rare judge who believes he understands absolutely every piece of information that he may be presented with. The average judge may have very little grasp of the scientific probability ratio’s that underlie DNA evidence or the minutiae of the refractive index of glass. However, these issues can be central in a trial and it is thus essential if justice is to be done that a judge understands the evidence. The problem is that much of scientific advice will be opinion based, furthermore science is generally accumulative and thus inevitably there will be a degree of reliance on the work of academic peers. These attributes cause all expert evidence to fall foul of two large exclusionary rules of evidence: Hearsay and Opinion evidence. The situation thus becomes highly complex because there is an inherent tension between the principles that state such evidence is unreliable and the perhaps more fundamental principles that require any decision that may deprive an individual of liberty or property to be based on a rational and cogent basis. As we continue we will see that these principles are the guiding principles for the judiciary and that the substantive law that govern the admissibility of expert evidence embody such principles. However, their position as an exception to the rule also place an inherently contra proferentem approach whereby the courts are likely to construe the meaning of such exceptions narrowly. The inconsistency between the rules highlights a further dimension; that overall the philosophy that is guiding the growth and formation of law in this respect is far from clear.

Opinion Evidence and Its relationship to Expert Evidence

Mr Smeaton understands the construction of harbours, the causes of their destruction and how remedied … I have myself received the opinion of Mr Smeaton respecting mills, as a matter of science. The cause of the decay of the harbour is also a matter of science … Of this, such men as Mr Smeaton alone can judge. Therefore, we are of the opinion that his judgment, formed on facts, was proper evidence
- Lord Mansfield, Folkes v. Chard (1782) 3 Doug KB 157

The issue of expert evidence is fundamentally based on practicality and common sense, unfortunately it suffers from the common deficiency of such concepts; it is incredibly difficult to translate such a nebulous concept into prescriptive rules of law. The problems associated with the concept will become apparent as we continue this discussion but just as this point I want to make clear the critical model that I’m using to assess the law in this area as it makes a large impact to the direction of the whole work. Lord Mansfield above pointed out that the evidence was taken as science and therefore as objective, these criteria for why we accept evidence are not exhaustive and as we shall it is a highly varied concept.

Frederick Schauer has written on a particularly interesting aspect of legal rules that examines the correlation between the background moral, social &c… and their translation into law. Schauer hypothesises that in a society where all the people agreed on the content of moral principles there would still be a problem over the conversion of these moral principles into coercive and authoritative social rules i.e. Law . This is because for such rules to be authoritative they must be formal and strictly applicable and actually supplant moral principles . However because these rules are…

‘…promulgated by human beings of finite reasoning & informational capacities & that are meant to improve the moral condition of human beings of finite reasoning and Informational capacities will always fail to capture precisely the requirements of morality’

It is this so called ‘asymmetry of authority’ that this work is going to be sensitive to for the first section, the distinctive needs and justifications for expert evidence as compared to the letter of the law. It is, as stated above, highly improbable that given our finite reasoning that the law is wholly satisfactory therefore the aim is merely to assess whether the rules are under or over-inclusive as regards the justifications that we will discuss in this work. I mention this here so that the reader is fully aware of my aims at the outset.

The common law ban on opinion evidence except in the case of experts is generally traced to Lord Mansfield’s dicta in the Folkes case, above, however the recognition by society that in some cases the use of experts can be an aid to the arbitration of justice dates to significantly earlier. Hodgkinson cites the 14th century case about mayhem which is mentioned in Buckley v. Rice Thomas as an early authority whereby surgeons where summoned to assist the court as to whether particular wounds constituted mayhem or not because the judges lacked the requisite skill to reach a conclusion. In Buckley Saunders J made an obiter dicta remark which summed up one of the main justifications for admitting expert evidence at the time:

‘If matters arise in our law which concern other sciences or faculties, we commonly apply for the aid of that science or faculty which it concerns, which is an honourable and commendable thing in our law’

However, at the same time as this the law was woefully inept to cope with some of the more subtle distinctions that exist within our modern day legal framework. When we realise that certain evidential rules developed much later, for example at the time of Buckley an accused was not even allowed to have witnesses or even a proper defence to a murder trial. These rules developed over time and the eminent evidence scholar John Wigmore has argued that importantly for the issue of expert evidence the willingness of the courts to rely on expert evidence was very much unguided by any formal principles until the distinction between opinion and factual evidence became more formed . The understanding of the interrelationship between expert evidence and the exclusionary rules on hearsay and opinion evidence becomes at this point, the early nineteenth century according to Wigmore, vital.

On a reading of the older sources prior to the advent of this distinction the courts have no clear principles guiding them. This is not per se a bad thing because it is arguable that later distinctions, particularly driven by the scientific approach to law taken by enlightenment scholars such as Bentham and Wigmore have, in the light of modern day post-modernist and realist critiques, lost much of their poignancy. However, the distinction between opinion and fact is dominant in the jurisprudence of the courts and is a very traditional part of the law of evidence. The justifications given for this ban on opinion evidence are traditionally four fold ; primarily the opinion of non-expert usurps the function of the jury and could lead to an undue influence being exerted by the witness on the jury members, this was pointed out by Vaughan CJ in Bushell’s Case :

‘The Verdict of a Jury and Evidence of a witness are very different things…a witness swears but to what he hath heard or seen, generally or more largely, to what hath fallen under his senses. But a Juryman swears to what he can infer and conclude…’

Another reason is that opinion evidence is largely irrelevant, which makes common sense when we think about the situations in which the rule operates. It is irrelevant if a non-expert opinion is given on an area requiring expertise as that person simply does not have the substantive knowledge to back-up an assertion of opinion. Furthermore if an opinion is given where no expertise is needed, quite apart from the prejudicial effect it may have, it is irrelevant as the decision maker is perfectly capable of forming their own opinion on the facts. Thirdly, a witness cannot be prosecuted for perjury as regards their opinion, or liable in tort for negligence , the law therefore doesn’t provide for any safeguards on the veracity of witness opinions. Finally, there is an established fear that the proffering of an opinion might circumvent other exclusionary rules such as relevance, hearsay and the findings of other tribunals . The last justification appears to lack a degree of poignancy because the other exclusionary rules are widely known and therefore an opinion can be treated just like any other item of evidence and be excluded if it falls under those exclusions.

The impact of this distinction was revolutionary when it started to infuse legal practice in the 19th century because before the fact / opinion divide was understood and substantive laws developed to represent such concerns, the use of expert witnesses was an ‘aid’ to the court that was where the reflection ended. The opinion / fact divide means that expert witnesses become an exception in their own right and thus identifiable as a particular class of evidence. This subtle change in perception means that the internal justifications of exception evidence come into play. They are an exception to a general rule and therefore the admittance of expert opinion has to be more strictly understood and that is why we see a lot of case law, in the late nineteenth century and twentieth century, that begins to flesh out the jurisprudential and substantive dimensions of the exception as awareness of the competing concerns in this area begin to infuse the judiciary.

In discussing the justifications for the expert witness exception Hall & Smith describe the overall approach that the court takes to the exception as being a rule that ‘opinion of scientific men upon proven facts may be given by men of science within their own science’ . However the tension between expert evidence and opinion evidence is exhibited in how that overarching principle is translated into law. The purpose of the following sections is to show how the basic tensions that exist in the above internal justification give rise to different problems. An understanding of the basic justification given for using experts is immeasurably useful and ought to be borne in mind; we may well be critical in the way that the need for experts is translated into substantive law but at no point are we critical of the de facto use of experts.

1. Contradiction of Expert Evidence Law

Hodgkinson refers to there being a contradiction at the centre of expert evidence which can be clearly understood when we think out the problem logically . Opinion evidence is predominantly excluded for its prejudicial effect and usurpation of the role of judge and jury, as we shall see below. The various exceptions for experts are complicated but they represent a mix between the common law reservations over opinion evidence and the need for aid in fields of expertise that it is impossible for judges and juries to make an informed decision upon. However when contradictory expert evidence is placed before the court, both of which have equal validity because of their backgrounds, the court is back in square one, as the great American judge and jurist Judge Learned Hand stated:

‘How can the jury judge between two statements each founded upon an experience confessedly foreign in kind to their own? It is just because they are incompetent for such a task that an expert is necessary at all’

The main culprit in these circumstances is the adversarial system as Davies points out:

‘If we were to…to design a system for the resolution of questions involving expertise, we would probably start with the idea that an expert, or a panel of experts, should decide such questions. If someone were to suggest to us…a person who had no expertise would decide such questions after hearing competing arguments from opposing experts, we would dismiss it as bizarre’

There are a number of reasons why the contradiction in expert evidence is symptomatic of the flaws of the adversarial system. Primarily the dichotic straightjacket that such a system forces on the presentation of evidence, especially in criminal procedure, is not suited to the presentation of scientific arguments, many do not admit of conclusive answers and cannot be wholly presented as supporting one party’s narrative. Nevertheless a retained expert may suffer from what is called the adversarial bias whereby they’re encouraged to expand on the evidence that supports one side’s narrative. This practice in itself exacerbates the contradiction of expert evidence, Davies quotes an Australian judge who referred to two cases where scientific knowledge was required and two diametrically opposed scientific opinions were given , the quandary this leaves for the judge is two-fold. The judge or jury must assess to what extent the evidence being presented is the result of adversarial bias and what is the whole picture, the more complicated the problem the more difficult this inevitably becomes. Secondly, the judge has to come to a decision which is right and therefore requires more than anything an independent expert to help them again the need will be greater in situations of greater complexity. When we consider the general demographic of the judiciary in most cases being those well into middle-age and consider that, especially in cases of Intellectual Property, they may fall to consider some advanced technological concepts which would be wholly alien to their general education then we can see how difficult the situation may become.

There are a large number of potential solutions to these problems none of them are ideal however for our purpose the mere realisation of the dimensions of this problem are what is important. The justifications and competing arguments that we will discuss regarding prejudicial effect, aid, justice &c…which inform the main common law principles of expert evidence all have problems or distortions when they are translated into practice. This problem is one of many with the expert witness system because it means that the very reason for the exception to the exclusionary rule on opinion and hearsay is undermined. If the adversarial system causes expertise to be cancelled out then given the time, expense and potential injustices that can arise perhaps they are not the aid to the courts that they once were. If their opinion is known to be diametrically opposed by a similar expert then their opinion is as good as the judges’ or jury members’ and as they can be no aid, consequently they are frivolous and potentially prejudicial.

2. Ultimate Issue & Information in the Public Domain

The Expert Opinion must be based upon the facts, if there is an error as to the facts then the Expert may not, however skilled, give his opinion on the issue . The opinion is considered to be ‘valueless’ in the same ways as normal opinion evidence. The opinion proffered also has to be necessary in order to aid the understanding of the decision-maker in a particular case. A good comparison can be made in this respect between DPP v. Jordan and DPP v. AB & C Chewing Gum Limited because these cases both revolved around the impact of obscene publications on people. In the Jordan case the court upheld the ideology that jurors were able to make up their own minds and did not need expert psychological evidence as to the effect of obscene materials:

‘They cannot be told by the psychologist or anyone else what the effects of the material might be…since the decision has been given to the jury as representing the ordinary man, it follows that, as matters affecting the ordinary man, the jury, as such, must make it’

This approach has debarred certain types of evidence, one such type of evidence, which was paradigmatic until recently , is that of expert evidence as to witness credibility. This approach is not unanimously supported for example in Scotland there are a number of cases and articles on the issue. Raitt has suggested that in certain cases there is considerable doubt over whether or not a typical juror or judge can understand the issues that may effect witness credibility. The examples that she gives is victims of domestic abuse and victims of child abuse, the nature of these crimes and the potential psychological effects on a witness are potentially completely alien to the experience of most jurors and judges . In R v. Turner the court laid down the reasons why such evidence ought not to be admitted:

‘authority for the proposition that in all cases psychologists and psychiatrists can be called to prove the probability of the accused's veracity. If any such rule was applied in our courts, trial by psychiatrists would be likely to take the place of trial by jury and magistrates’

The courts have now reconsidered that the science is now stable enough and as we shall see the intermingling between this issue and the issue of reliability is quite large. The development of this rule in comparison to some of the continental jurisdictions gives us an interesting comparison of the underlying motivations in the UK system. The judge in both South Africa and other civil law jurisdictions posit the judge as the ultimate trier of fact so the test laid out in Turner as to the admissibility turning on the helpfulness is treated more literally. The judge asks whether this or that piece of expert evidence would truly be of use to him in coming to a decision in the particular case. However, as we have seen above the concern of English law is not so much on a strictly ‘helpful’ basis because it is interpreted to have more to do with the Ultimate Issue rule that we will discuss below. This means that there is an emphasis on the normal / abnormal sphere divide and the judges sit as arbiters of that divide. The arbitrary nature of this divide has been questioned using similar studies to that of Raitt, above, and the point has been made that ‘much common behaviour is 'demonstratively counter intuitive in the sense that "ordinary men and women" generally misunderstand [it]’ .

In A,B &C the court considered another prosecution under the Obscene Publications Act 1959 similar to Jordan however as the target audience was children rather than adults, psychological evidence was allowed because ‘any jury and any justices need all the help they can get’ when it comes to children. Lord Wilberforce commenting on the nature of the distinction in Jordan stated:

‘To this general rule there may be an exception in a case where the likely readers are a special class, such that a jury cannot be expected to understand the likely impact of the material upon its members without assistance. In such a case evidence from persons qualified by study or experience of that class may be admissible’

This kind of distinction is seen across the board as regards expert evidence and forms a wider rule that the opinion of an expert is not necessary or helpful where there is not some identifiable body of science which is not considered to be understandable by the average person . In R v. Masih the court specifically stated ‘in order to enlighten the jury upon a matter which is abnormal and therefore, ex hypothesi, presumably outside their experience’ then expert evidence will be allowed. The decision is one of pure discretion and a systematic study of what is allowable would be almost obsolete by the time it was written because of the variation in what is considered in the public domain. Zuckerman specifically states on this issue:

‘A judge deciding whether expert opinion should be accepted as an arbiter of a certain matter has to consider the state of public opinion on the point. If the community has come to defer to professional standards on the matters in question, the courts will normally follow suit’

This issue will become more pertinent later on when we discuss the courts attitude to new technologies and medical evidence. The law has exhibited a degree of incoherence and particularism in its application of the normal / abnormal divide which is, as we stated, inherently likely to occur because of its discretionary basis. In R v. Lowery which allowed psychological evidence in the case of two adults, on the face of it this seems to be contrary to the decision in Jordan above and the general rule against having expert evidence on an area considered in the public domain. In that case Lord Morris justified his admittance of such evidence by stating ‘When an accused person put his character in issue, he is in effect asking a jury to take the view that he is not one who would be disposed to have committed or would be likely to have committed the crime in question… if an accused person is not of good character, the law has been firm’ . This tenet of the law has become one that centrally justifies the existence of the rule, the expert’s role has always been one of ‘aid’ since its very inception however that aid is circumscribed to fall only in those categories which the court decides it requires such aid. However, the tension between the aid an expert opinion can give the court and the perceived potential prejudices of such aid mean that the law goes onto circumscribe the role of an expert.

The distinction that Lord Wilberforce was making in Jordan is significantly related to the more fundamental rule that Expert Witnesses cannot give evidence on the ‘ultimate issue’. This concept is very vague but is a product of both the tension I mentioned above between the expert evidence exception and the general rules of evidence as well as the potentially determinative weight that will be given by a lay person to such evidence. The basic premise of the ultimate issue rule is that the expert shouldn’t give an opinion on any issues which it is for the judge or jury to decide, the classical position was outlined by Cresswell J in National Justice Compania Naviera SA v. Prudential Assurance Co Ltd where he remarked that ‘An expert witness should provide independent assistance to the Court by way of objective unbiased opinion in relation to matters within his expertise’ . The idea of ultimate issue is perhaps best understood by use of an example. It would be inappropriate to ask a medical expert in a medical malpractice case whether the accused’s behaviour fell short of that required by a professional doctor. However, Lord Taylor, in a separate case in the same year as National Justice, made an obiter dicta remark about the practical operation of the rule:

‘The rationale behind the supposed prohibition is that the expert should not usurp the functions of the jury. But since counsel can bring the witness so close to opining on the ultimate issue that the inference as to his view is obvious, the rule can only be…a matter of form rather than substance’

Thus, in our malpractice situation we can see how a skilled advocate might ask questions which have obvious inferences on the standard of the accused’s behaviour by directing the expert to explain what common medical practice in the particular situation is. As an ancillary issue to those started here it is worth pointing out that the courts have made it quite clear that they need not accept the experts advice, as was stated in Re B (a minor) (care: expert witness) ‘the parties have invoked the decision of a judicial tribunal and not an oracular pronouncement by an expert’ . This situation was discussed in Liddell v. Middleton where the judges were highly critical of the parties in bringing expert witnesses in a road traffic accident where there were eyewitness accounts and they specifically stated:

‘There has been a regrettable tendency in recent years in personal injury cases, both road traffic and industrial accidents, for parties to enlist the services of experts whether they are necessary or not. When they are not necessary, they simply add to the already high cost of litigation and the length of the trial’

However the judge must not simply substitute his decision for the expert’s where there is nothing to contradict unanimous expert evidence in favour of the accused . In Bolitho v. City and Hackney Health Authority Lord Browne-Wilkinson discussed the role of the judiciary and whether it was one of deference or education, primarily he laid town a test that where in certain cases ‘it cannot be demonstrated to the judge’s satisfaction that the body of opinion relied on is reasonable or responsible’ furthermore he went on to state his opinion on the level of deference a judge ought to pay to an expert:

‘In my view, it will very seldom be right for judge to reach the conclusion that views genuinely held by a competent medical expert are unreasonable. The assessment of medical risks and benefits is a matter of clinical judgement which a judge would not normally…make’

The rule on ultimate issue may well be under threat if we are to believe the dicta of Lord Taylor above however there are definite limits. The ultimate issue rule does still exert a certain pressure in determining the line between what is acceptable and what is unacceptable in actually giving evidence for example the courts have been quite clear that an expert should not under any circumstances opine what he would have done if he was in similar circumstances to that of the accused . One of the more recent decisions on this issue was in Pride Valley Foods Ltd v. Hall & Partners (Project Managers) where Toumlin J was very emphatic in his condemnation of the reports prepared in that case, he specifically relied on Pozzolanic Lytag Ltd v Bryan Hobson Associates and the judgement of Dyson J in that case, Toumlin J in particular stated:

‘Many of these are questions for the court and not questions for the experts… He purports to make many findings of fact on questions which are matters for the judge…His report offends against the established basis on which experts should give evidence’

It must be remembered that these cases are civil cases and as such the rules are slightly distinct however as regards the rule on ultimate issue both the civil and criminal seem to have identical tests.

The academic commentary on this rule has also been unfavourable and it is claimed that the rule is open to a very large degree of criticism. The main justification of the rule is premised on a belief that the jury might be overly influenced by an expert which is a false assumption in the case where it is a professional judge sitting alone. It has been said to in fact be wholly antithetical to the whole underlying justification for having experts namely that ‘the drawing of inferences from the facts in question calls for an expertise which the tribunal of fact does not possess’ . A final reason why this rule is considered to be inconsistent is that there is a high frequency of disagreements between experts in the case law in any case so it will be very rarely that there is unilateral incontrovertible expert evidence in favour of one party. Therefore the prejudicial effect of this rule has to be questioned, reinforced by its absence from the Civil Law of procedure and its almost complete invisibility from day to day Criminal law procedure . The problem with such an approach of quasi-existence is clearly undesirable and offends against principles such as the rule of law.

The law has always recognised that experts have a role to play however what was described by Wigmore as the fact / opinion divide was part of a whole movement in philosophical, jurisprudential and evidence scholarship which insisted on the use of exclusionary rules of evidence. Holdsworth in discussing this development identified that these exclusionary rules of evidence were the work of the sixteenth and seventeenth century and in particular the rise of the belief that ‘law of evidence…is distinct from the logical processes of reasoning; but it is based upon and assumes the existence of these processes’ . Holdsworth is making an interesting point here, which is related to our exercise, in that many of modern day evidential rules such as burden of proof and exclusion of certain facts as inadmissible flow directly from instinctive reasoning processes and the application of logic in a system of relative free proof:

‘Thus the rules which flow obviously from the principles of reasoning have been overlaid by a mass of technical rules, which represent the ideas and needs of many different periods in the law of procedure’

Twining again referring to this sort of overlapping and intermingling progression of the rules of evidence identifies that there are many competing concerns . He identifies the rule of Hearsay as starting around the sixteenth century, so we may reasonably infer awareness of the issues of opinion evidence and experts as an exception to that point. The issues we raised in this section regarding the role of expert as an aid and also the restrictions on testimony as to the ultimate issue show these competing concerns. Clearly the dominant concern in excluding opinion evidence is that the evidence could potentially be considered by a decision-maker despite its potentially unreliable nature however, in some cases an informed opinion will not be unreliable and thus in those situations an expert will be allowed to aid the court.

The concerns regarding experts only being called in cases where there is a genuine area of expertise not in the public domain were exemplified in R v. Turner, above, where it was stated that the existence of scientific qualifications and use of scientific jargon on matters of normal human behaviour may not be ‘any more helpful than that of jurors themselves; but there is a danger that they may think it does’ . The danger of overemphasis on pre-ordained unreliable evidence is one of the central motivations for the exclusionary rules of evidence and we can see it playing a large role here. The rule on no evidence on the ultimate issue furthermore exhibits such a sensitivity to background principles and the courts’ approach is clearly motivated by the desire to avoid trial by expert. However, the obvious artificiality of this test, as recognised in Stockwell, has forced reconsideration in the logic which motivates this rule. Robertson & Vignaux point out that an expert in expressing an opinion as to the ultimate issue may well make certain assumptions about prior odds. The main example would be where a forensic expert giving evidence as to the match between the accused’s blood and that found at the crime scene expresses an opinion as to the accused’s guilt. There are certain assumptions that an expert may be making which may be invalid and it is wise to bear in mind that an expert may well only be operating from a more limited set of facts than the court has available to itself .

The understanding of these various competing concerns is interesting because to a degree the problems in the rules that we identified cut both ways. The background principles are translated into rules that in some sense are both under and over inclusive. The need to rely on experts but the desire to limit their privileged position in giving an opinion to the court appear to war against each other.

3. Peritus and Role of the Expert Witness

Another basic common law rule which tells us a lot about the way that the law treats expert opinion is the fact that an expert witness need not have any formal qualifications as such but the judge will determine whether he exhibits a sufficient degree of expertise. The leading case in this area is R v. Silverlock where a solicitor who had gained expertise in handwriting comparison through an amateur interest in the area which had been put into practice. Lord Russell CJ stated that there was no test of expertise rather the correct approach was for the judge to ask ‘is he peritus? Is he skilled? Has he an adequate knowledge? Looking at the matter practically, if a witness is not skilled the Judge will tell the jury to disregard his evidence’ . In more modern times the law has upheld ‘informal’ experts in various situations such as a police officer’s experience in traffic accidents qualified him as an expert . In Westminster City Council v. McDonald the court held that expert opinion as to noise was admissible even in the absence of sophisticated technology or techniques. The best summing up of the law was given by Tyrwitt Drake CCJ in R v. Bunnis :

‘The test of expertness, so far as the law of evidence is concerned, is skill, and skill alone, in the field of which is sought to have the witness’s opinion…It is not necessary, for a person to give opinion evidence of a question of human physiology, that he be a doctor of medicine’

The interesting thing about the approach of the courts here is that it uncovers a more liberal approach in the courts thinking, a willingness to treat expertise at face value and not debar certain origins of those expertise. The common law rules we examined in the previous section were borne of a tension between the competing concerns of the court. Commentators have questioned this approach, especially in light of the ‘obvious dangers’ of relying on expert testimony of a ‘questionable reliability’ . The approach is also not precisely harmonious as ss 1(1) and 2 of the Criminal Procedure (Insanity and Unfitness to Plead) Act 1991 require specifically qualified experts before an acquittal based on the defence of Insanity only on the basis of two or more registered doctors, at least one of whom is approved by the Secretary of State as having appropriate expertise. However it is clear that this is an accepted approach given that an identical test is administered in other jurisdictions . This seems to be adequate evidence that there is scope for variation on this point.

The role of the expert witness is also an interesting position, unlike other witnesses who although sworn to tell the truth do not owe a duty to the court above that of the party calling them. An expert witness does and Lord Wilberforce commented on this aspect in Whitehouse v. Jordan stating that ‘whilst some degree of consultation between experts and legal advisers is entirely proper it is necessary that expert evidence…should be…the independent product of the expert, uninfluenced as to form or content by the exigencies of litigation’. The somewhat nebulous definition was given considerable judicial attention in the case of National Justice Compania Naviera SA v. Prudential Assurance Company Ltd where the court set out a number of key aspects of the role of the expert witness:

• Objective unbiased opinion to matters within his expertis
• State the facts upon which assumptions are based
• Make it clear when an issue falls outwith their expertise
  
• If there is insufficient data then he should inform the court that opinion is provisional
  
• Any change of views after an exchange of reports should be communicated to the other side.
  
• Any real evidence upon which opinion is based should also be provided.

This is summarised by Swann as boiling down to a general duty for the expert to ‘advise the judge, to undertake assessment, to give an opinion and consult with other experts’ this was all to be done in a spirit of ‘integrity and objectivity’ .

An interesting set of facts occurred in Liverpool Roman Catholic Archdiocesan Trustees Inc v. Goldberg (No 3) where it was admitted by the expert that he had a personal relationship with the defendant. The judge felt that it was just as important that justice is seen to be done and therefore the lack of independence on the part of the expert making him more favourable to one party made his evidence inadmissible. This case highlights the tension between the judiciary’s commitment to having the aid of an expert to understand the full facts of a case and in turn upholding the ideology that certain evidence ought to be excluded because of its potentially prejudicial effect. Although not directly concerned with the role of the expert it is a further limit upon their ability to appear in a court of law. It has been stressed by many commentators that fundamentally the right of an expert to appear in the court and not to be subject to the strictures of normal evidence law is to be treated as a privilege . This privilege has been extended in a haphazard and often incoherent manner and it is not altogether unsurprising that academic attempts at rationalisation will generally fail to capture the entire nature of the courts approach.

The role of the Expert witness in the legal arena has been an area of great controversy for the last decade ever since the ‘Access to Justice’ reports in the mid-1990, also known as the Woolf Reports . The focus of Lord Woolf was the prohibitive cost of litigation which was in part contributed to by the ‘multi-million pound fee income’ industry that pervaded professions as wide and varied as Accountancy and Architecture. In addressing one of the major problems that this presented for both the Criminal and Civil Justice system Lord Woolf considered the main problem was that the adversarial system had a distortive effect on the role of the Expert:
‘There is wide agreement that the expert's role should be that of an independent adviser to the court, and that lack of objectivity can be a serious problem…The present system has the effect of exaggerating the adversarial role of experts, and this helps neither the court nor the parties’

The tragic miscarriages of justice in the cases of Angela Cannings, Sally Clark and Trupti Patel show that even the limited reforms that flowed from the Woolf Reports have not improved the situation, at least not in the Criminal Justice system . There are numerous medical and legal articles detailing the fact that experts feel an inherent pressure from a solicitor in presenting evidence and there is a great deal of cynicism, as shown by the observation that ‘it is quite surprising to see with what facility and to what extent, their views can be made to correspond with the wishes or the interests of the parties who call them’ . A leading report was published in 2004, in the wake of the criticism of Sir Roy Meadow’s evidence in the Clark and Cannings trials, by the Royal College of Pathologists and the Royal College of Paediatrics and Child Health Care which again highlighted that medical experts in trials were falling prey to the pressure of giving evidence in support of their ‘side’ and furthermore they were relying a lot more on ‘medical belief rather than scientific evidence’ . The adversarial bias was hoped to be solved by the Woolf report with reference to a prescriptive duty on the expert witness that ‘provide[s] that when an expert is preparing evidence for potential use in court proceedings, or is giving evidence in court, his responsibility is to help the court impartially on the matters within his expertise. This responsibility will override any duty to the client’ .

Whilst, as I have mentioned above, we have to be careful about drawing analogies from the civil sphere given that there are quite distinctive approaches to expert evidence, in this issue like the rule on evidence as to the ultimate issue there is a significant degree of overlap. In Cala Homes (South) Ltd and Others v. Alfred McAlpine Homes East Ltd there was a lesson for any budding expert witness to take on board as Laddie J ripped an experts evidence to shreds because of an attitude displayed in an article he had published where he intimated that his opinion was that an expert should treat a judge as a ‘rustic’ who could be susceptible to a Three Card Trick by presenting an argument wholly favourable to the side instructing the expert. Laddie J stated in this issue:

‘Most witnesses would not be prepared to admit at the beginning of cross examination, as Mr Goodall [the expert], effectively did that he was approaching the drafting of his report as a partisan hired gun. The result is that the expert’s report and then his oral evidence will be contaminated by this attempted sleight of mind’

Laddie J had admitted that Mr Goodall was an eminent Architect in his area but as a result of this tendency to completely ignore his duty to the court and present a wholly one sided argument the judge stated that in coming to a conclusion on the issues at hand in the case he had effectively ignored Mr Goodall’s advice. This is obviously an extreme example of somebody who tempted the wrath of the court by espousing a highly derogatory opinion that judges could be deceived by the trickster expert. Nevertheless, the question that begs itself is how many people read the article by Mr Goodall and accepted his advice? These people can go undetected and their prejudicial advice could have a serious impact on the direction of the case . Furthermore this problem is undoubtedly exacerbated by the pressures from clients on solicitors to produce partisan expert witnesses. It is clear that this pressure will be of the utmost in a criminal case where the stakes for the client are his liberty. The adversarial culture which reveres the art of advocacy and persuasion undoubtedly has its own inimical pressures to win which it is hard to see being dissipated whilst the decision to call experts rests in the hands of the respective parties. The solutions that have been suggested by reports such as Woolf have had little impact so far and there are still reports of adversarial bias that surface regularly

The idea of imposing a duty of neutrality on an expert witness in an ironic manner exhibits the precise ignorance of the true nature of science in the courts that causes so many problems in relation to expert evidence. There is an unchallenged assumption that in relation to experts that somehow forensic science and pure science are the same thing or at least share common principles. The main one for our purposes is the assumption that they conceive all science as the ‘disinterested pursuit of the truth under ideal conditions of inquiry’ however in general most crimes do not start with ideal preconditions such as uncontaminated environments and unlimited source material. The realisation of the extent to which ‘behind this apparently objective, definitive conclusion lies a succession of more subjective and equivocal judgements’ impacts considerably on the status we attach to experts. The problems is that as a general rule the answer ‘I don’t know’ is rarely seen as an acceptable answer and any attempt to highlight these numerous subjective steps may well be flawed and reduce the evidence to incomprehensible. It will be flawed primarily because many of the subjective leaps may be subconscious.

A further dynamic that ought to be considered in marrying the role of the expert to that of the courts is the simple fact that the system of criminal justice is not an out and out search for the truth . The complaint sheet, which is served on an accused in a criminal case will usually see a summary of the facts of the case, the case then proceeds on the truth of the allegation and not on the truth of the whole circumstances. Positing an expert as an independent advisor to the court doesn’t sit well with this position because it is inimical to the position of the parties. If it goes to trial then the accused is pleading not guilty, in effect denying the allegation, the defence are not going to call an expert witness who may give prejudicial evidence for their side. An interesting judgement was handed down in the case of Manchester City Council v. B by Justice Bracewell because it dealt with two medical experts who were declared to have exhibited a considerable degree of disagreement . In this case there was no discussion of adversarial bias however the judge did refer valuably to her thought process. She felt that the distinctive conclusions that the scientists came to in this case where not as different as they first appeared because:

‘Each expert draws on their own clinical experience together with the research evidence. It is not, and cannot be, an exact science because assumptions frequently have to be made by medical experts as to the basic underlying and background facts and any differential diagnoses’

Justice Bracewell seems here to be making a point which goes directly to the heart of the issue in this case which is that adversarial bias is one factor but the nature of forensic science is another. This case is not overly reported and I only found reference to it in one article and even then it was fleeting. However, I think that as we begin to build up a healthier understanding of the controversies that the role of the expert evidence can raise, this dicta suggests taking a novel and simplistic approach to expert evidence which is to take as a pre-requisite that scientific differences can be weighed in an ordinary judicial manner with reference to underlying assumptions that experts may have made. The recognition of scientific conclusions being sensitive to their initial conditions is hardly revolutionary but laid down in some form of statutory or informal guidance to the judiciary this kind of approach could significantly impact on the coherence and unanimity of decisions on expert evidence.

A different approach was suggested in the case of Re C where the judge was of the opinion that there ought to be collaboration between all the experts brought before the court before they presented evidence. The advice presented ought to be in the form of two conclusions on each of the two competing allegations. This approach whilst in some ways beneficial also has to be criticised given that these conclusions are discussed out of the courtroom and opinions may harden where before they were more flexible.

The Criminal Justice Act 2003 now requires the defence to disclose any medical reports that it may commission in the preparation of the case, whether presented in evidence or not. The problem with this situation is that it is far from clear that this will somehow help overcome any adversarial bias on the behalf of experts or deal with the problem of the nature of the adversarial system. It will merely suppress the use of experts by defence agents, even in cases where expert evidence could be of vital importance. The rationale for such a change is difficult to accept as ‘the only people who would take such a blind risk are those with nothing to lose. Perhaps those in authority take the view that the innocent have nothing to fear’ . Any proponents of that particular view should ask Sally Clark if she feels the innocent have nothing to fear from the use of experts.

The issue of the role of the expert is one which is fraught with difficulty and contradictions. Science is not suited to give definitive advice on one side of the problem, therefore different scientists will come to varying conclusions; the judiciary has no such luxury it must come to one definitive solution. The adversarial system prima facie would seem to be the best forum for such differences of opinion to be resolved in. The classical notion of two opposing sides evincing the most cogent evidence on their side putting all the evidence before an independent judge in theory seems ideal. However, the adversarial bias and the tendency of experts to overstate their science or present their conclusions as definitive are unhelpful and could lead to serious miscarriages of justice. The issue certainly seems to fit the colloquial saying ‘damned if you do and damned if you don’t’.

4. Daubert & The Extent to which we utilise Expert Evidence

This is the final section of our discussion of the general principles of Expert evidence and touches on a number of the issues that we have discussed before in regards the admittance of expert witnesses. In the American case of Daubert v. Merrell Dow Pharmaceuticals Inc. the United States Supreme Court discussed when the courts generally ought to admit expert evidence and the test that they formulated has controversially been used around the globe. This subject matter more than any has churned out a library worth of resources, the full breadth of which it is not possible to give here. This issue is particularly controversial in the U.S.A however, whilst this issue is extremely important and raises a lot of insightful points we must avoid becoming blinkered and realise that the sociological pressures of the world of Expert evidence can be particularly demanding on any expert in particular the lack of suitability for the presentation of scientific hypothesis in determinative statements of fact in the trial setting .

The simple wording of the judgement belies its effect on the role of the judge in allowing expert evidence the court stated that ‘the trial judge must ensure that any and all scientific testimony or evidence admitted is not only relevant, but reliable’ . The concept of reliability has lead to the casting of the judiciary as the gatekeepers in this respect and the Daubert court emphasised three factors which would generally guide the judiciary in coming to a decision over the reliability of an expert . The first was whether proper methods of hypothesis testing were used, flowing from this the judge ought to be able to tell whether the result was falsifiable. Furthermore they need to consider the failure rate of the method and the standards controlling the technique in question. Thirdly, they ought to consider the level of peer-review and acceptance that such techniques generally attract in the scientific sphere that the work is concerned with. The court in Daubert summed up by stating that their may well be a place for the test of general acceptance:

‘Widespread acceptance can be an important factor in ruling particular evidence admissible, and 'a known technique which has been able to attract only minimal support within the community' may properly be viewed with skepticism’

The general test is one of scientific validity, it is arguable whether judges and juries are qualified to be the decision-makers in such cases as they suffer from very much the same flaws as the whole of expert evidence; The non-expert deciding which experts is reliable.

This pro-active role for the judiciary is claimed not to be mirrored in this country which has until recently had comparatively lax standards and accordingly is argued to increase the risk of error It is in regard to two recent decisions that this kind of role for the UK Judiciary has been brought into question. In R v Dallagher the court relied on a nascent science of ear print identification which was regarding an ear print left on a window at a burglary scene, on appeal the court found the prosecution to be unsafe because of the unreliable evidence. In R v. O’ Doherty the court came to consider again similar voice recognition technology as the court considered in R v. Robb . However, the more permissive approach that had been exhibited by the court in Robb was directly overruled and the court refused to admit what they considered to be unreliable expert evidence. These two recent decisions seem to have exhibited a more cautious approach, which is closer to the US Daubert approach, it is suggested that this has a lot to do with the dicta in the case of R v. Gilfoyle which was about the use of psychological autopsy and its admissibility in a case of apparent suicide:

‘he had never previously embarked on the task which he set himself in this case. Secondly, his reports identify no criteria by reference to which the Court could test the quality of his opinions: there is no data base comparing real and questionable suicides and there is no substantial body of academic writing approving his methodology’

Lord Justice Rose then continued on and directly compared the decision in Frye v. United States , which Daubert was built upon, to the English case of Strudwick and Merry . He claimed that the law was the same both sides of the Atlantic in that ‘evidence based on a developing new brand of science or medicine is not admissible until accepted by the scientific community as being able to provide accurate and reliable opinion’. The O’Doherty case which is one of the most recent cases specifically avoided laying down any generalisations and stated ‘We do not seek to lay down precise guidelines as to the appropriate warning. Each case will be governed by its own set of circumstances’ . They also didn’t follow Gilfoyle and didn’t find Dallagher any use in coming to a decision, however the reasons proffered by the judges were, with respect, weak. The Court of Appeal specifically mentioned the sanctity of the jury in trial on indictment and the unwillingness of them to overrule a decision by the jury. However, they premised the fact the evidence against the accused used techniques which were redundant given the ease with which auditory techniques were now available. It was this that they premised the distinction between itself and Robb. However, as O’Brian points out this is not a logical way to distinguish the cases because if a certain type of evidence is unreliable then it was unreliable in Robb, furthermore auditory analysis alone was rare in the case of Robb. O’Brian submits that the Court of Appeal was forced to ignore the previous case law in order to achieve the just outcome. The overall impression in these cases is that there is a distinct tightening on the standard of the expertise required.

One of the largest problems for any such test of admissibility is that the court can not have a blueprint as to what sciences and what experts are ‘reliable’. In particular the problem that judges have to grapple with the problem that ‘the examples of cases in which expert evidence has been admitted range so widely that it is impossible to reduce them to particular forms of specialist practice’ . It is generally accepted that any attempt to categorise or simplify the general test of Daubert or the discretionary approach that we seem to be taking in this country is futile . However, one way of analysing the general attitude of the courts is to analyse the approach that the courts take to novel technology and sciences and because these are the penumbrary areas of admissibility they are on the frontier between admissibility and exclusion when it comes to expert evidence. In another influential US decision Frye v. United States the court stated:

‘Just when a scientific principle crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone, the evidential force of the principle must be recognised, and while the courts will go a long way in admitting expert testimony deduced from a well-recognised scientific principle or discovery the thing from which the deduction is made must be sufficiently established’

Hodgkinson argues that whilst not specifically acknowledged by the courts in the UK this is the approach generally that they take, certainly this principle is not inconsistent with anything in English law . There are not many examples but we have seen already that relatively nascent sciences such as ear print identification (Dallagher) and old techniques of auditory identification of voice prints (O’Doherty) are at the extremity of new and old sciences and will not be allowed by the courts. In searching for more direct authority on the approach that the courts ought to take to nascent sciences the courts have had particular reference to a passage from Cross on Evidence:

‘The better, and now more widely accepted, view is that so long as a field is sufficiently well-established to pass the ordinary tests of relevance and reliability, then no enhanced test for admissibility should be applied’

There have been some groundbreaking technologies reviewed in recent years which show that the courts are willing to interpret the incredibly nebulous concepts of ‘sufficiently well-established’ and ‘reliable’ as widely as possible. However, it would be incorrect to present a picture of a unified judiciary on these issues, in fact this area as we shall see is far from satisfactory and exhibits considerable problems of internal consistency. The widely accepted view may well be as Cross states above however this does not account for the discussion and endorsement of the US approach in R v. Dallagher. Furthermore in R v. Bonython the court stated another formulation which contained slightly different requirements:

‘the subject matter of the opinion forms part of a body of knowledge or experience which is sufficiently organised or recognised to be accepted as a reliable body of knowledge or experience, a special acquaintance with which by the witness would render his opinion of assistance to the court’

The issue of the evidence being of assistance to the court seems to be at odds with the approach in R v. Turner that we discussed in the introduction which talked about the ‘normality’ or ‘commonality’ of the science. Bonython implies a stricter test with concentration on the organisation of the evidence and acceptance by the scientific community. The distinctions between the various approaches of Turner, Bonython, Dallagher and Gilfoyle may be semantic or they may be substantive, without in depth sociological studies into the issue it is hard to say which one is the case. However, the confusion and the obvious lack of protection from particularistic decision-making is undoubtedly what have caused some of the worst excesses of our Criminal justice system.

In R v. Doheny and Adams the court fell to consider the application of DNA profiling. The issue of DNA profiling cuts across a number of barriers especially when it comes to testimony on the ultimate issue but for our purposes the interest is concerned with the approach that the courts took to its admissibility. The issues in Doheny were complicated but it boiled down to not the admissibility of DNA evidence per se but the way in which such evidence was presented to the jury. The position was that in expert forensic evidence on fingerprints the expert is allowed to give an opinion on the probability of the sample obtaining from the accused.

The problem that the court faces with regards to DNA profiling is the context in which DNA evidence is given to the jury because it can be potentially very prejudicial. This is not the stage to launch into an explanation of the various probability problems associated with DNA profiling. It will suffice to say that there is significant problem in calculating the probability of someone’s DNA being unique because it must include all potential people that could commit the crime and this will be affected by a number of extraneous factors. The court in Doheny has been criticised for oversimplifying the problems involved because they stated that the jury members could be informed of ‘the frequency with which the matching DNA characteristics are likely to be found in the population at large’ but categorically could not be informed of ‘the likelihood that it was the defendant who left the crime stain’ .

The criticism that has been levelled at the approach is that if the expert is not to be allowed to address the jury as to the probability that the DNA came from the accused then presumably the jury must make this calculation. However, it is difficult to guide the jury without giving an opinion or using complicated theorem such as Bayes theorem for calculating probabilities. The predominantly interesting issue for this work is how the courts differentiate between the relatively new technology of DNA profiling and fingerprint evidence, a technology that has been in use for over a century. Evett makes the point that DNA as a new technology has received far more scrutiny than Fingerprinting, and that fingerprint experts are allowed to offer opinions on the issue of the probability of that fingerprint being that of the accused. The background reasoning that underlies fingerprinting probability statements has been confused by the belief that the once 16 identical points had been found on the fingerprint that a match was a fact, this is no more true than probability statements based on a number of matches between loci on the accused DNA and the sample from the crime scene. The distinctive approach is therefore more based on practice than any coherent evidential principles:

‘When a fingerprint expert gives an opinion of identity of source he gives it with personal certainty…It is important to realise that this kind of opinion is a manifestation of a largely psychological process--it owes nothing to scientific proof and it cannot be substantiated by logic. This does not make it bad, or unreliable but it is not based in science’

Another recent case which fell to discuss new technologies was the case of R v. Nugent and Savva which discussed the facial mapping technology taken from CCTV images. The courts dicta in this case was rather strange given what we have written before- the court implied that despite the evidence having a number of potential flaw it basically argued that the evidence wasn’t enough to be considered ‘expert’ in the sense that facial mapping had been used in other cases. It was however still held to be relevant and not prejudicial. This seems to flow against the jurisprudence we talked about above, the useful presentation of information that was given as a justification does not form an exception to opinion evidence, expertise must be necessary and as we talked about above in relation to evidence that is could be understood within the normal / abnormal divide. In Nugent the court had reference to R v. Gray where the court had made a number of Obiter Dicta remarks about the general usefulness of facial mapping and enhancement as a technique in general. Interestingly the court took an extremely similar approach as they had taken in Doheny where they stated that ‘There is no means of determining objectively whether or not such an opinion is justified. Consequently, unless and until a national database or agreed formula or some other such objective measure is established, this court doubts whether such opinions should ever be expressed by facial imaging or mapping witnesses’ . The opinion they were referring to was probability statements about the image being that of the accused, the court went onto make a somewhat ambiguous distinction to the effect that the evidence would still be admissible so that the expert might be able to make statements as to certain combinations of characteristics that perhaps show similarity but their should be no opinion as to probability. They distinguished fingerprinting because it had an ‘accepted mathematical formula’ .

One of the most interesting cases, as we mentioned above was R v. Dallagher and the obiter dicta remarks from that case become of increasing importance when we consider that this is yet again another novel form of identification which has analogous attributes and purposes to fingerprint evidence as the paradigm in all the above cases. The court as we stated above found the prosecution to be unsafe completely due to the state of such science. However, we are now interested in analysing the remarks made in that case which we can extrapolate to a general approach. The court relied on a lot of cases and discussed the whole relationship of novel sciences to admissibility. The discussion of the court here is one of the most informative and encompassed a lot of the cases that we have discussed in this section and more. In particular one of the most progressive dicta’s which were cited with approval was one from Lord Justice Steyn in R v. Clarke :

‘It is essential that our criminal justice system should take into account modern methods of crime detection…There are no closed categories where such evidence may be placed before a jury. It would be entirely wrong to deny to the law of evidence the advantages to be gained from new techniques and new advances in science’

The court held that ear identification’s status as a relatively untested, un-peer reviewed and uncertain technology didn’t make it inadmissible. In keeping with a vast swathe of cases such as R v. Silverlock, R v. Gilfoyle, Clarke, Stockwell and even Daubert the court felt that such evidence was admissible. The fault fell in the way in which the jury was directed in Dallagher, they felt that the decision in Doheny had created a litmus test, that approach was endorsed as correct and the decision of the lower court in Dallagher was held as unsafe.

The courts came to consider another ‘science’ in the recent case of R. v Luttrell (Gerrard Francis) where the court admitted expert evidence on both the side of the defence and the prosecution on lip-reading, the commentary on this case makes, with very little reference to the other cases on novel sciences a point about the way such evidence is to be handled.:

‘Lip-reading evidence required a warning from the judge as to its limitations and the risk of error, not least because it would usually be introduced through an expert who might not be completely accurate…That imperfection did not render the material inadmissible, but it did necessitate a careful and detailed direction’

The court once again in this case therefore let in potentially unreliable evidence and then protects them by giving a direction to the jury on the reliability of such evidence.

The courts general attitude to novel sciences can therefore be stated as being one of extreme caution. The use of such expertise is clearly supported and there are very few cases involving novel sciences where the court has actually held such expert evidence to be inadmissible , as Steyn L.J. in Clarke stated ‘although at one time a more conservative approach had been adopted, the policy of the English courts has been to be flexible in admitting expert evidence and to enjoy 'the advantages to be gained from new techniques and new advances in science’ . The fault seems to lie with what is becoming known as the ‘prosecutor’s fallacy’ that there is a distinction between probative statistics and the opinion of the expert as to the probability of identity between the sample and the accused. Thus using the Doheny case again one can say that one in a million people are likely to have the DNA profile of that from the crime stain, thus the suspect will be one of about 26 people. The only further statement that can be made is that the accused is one of those 26. The probability of the accused having left that stain is for the jury to decide on the whole of the scientific and non-scientific evidence available to themselves. This appears to be the approach that the courts have taken. The approach accords with quotation from Cross above however it is more difficult from this perspective to analyse whether the courts are acting as safeguards to the reliability of such evidence as the judiciary in the US are.

The courts in the U.S. seem a lot more willing to question the methodology used by the expert and generally show a higher propensity to exclude evidence. A good example of this is from the case of Carnegie Mellon Univ. v. Hoffmann-LaRoche where the court found that the lack of peer review and the process not being followed by a minority of the scientific community made the evidence inadmissible rather than potentially unreliable. The US Judicial system also recognises specific Daubert motions which certainly exhibit more poignancy than a general movement for inadmissibility in this country which is based on ambiguous standards . The UK approach to reliability certainly seems to be less formal than that of the US.

It is clear from separate lines of jurisprudence that as a general rule of English law there is a duty upon the judge to warn the jury when certain species of evidence is considered to be unreliable. This issue was discussed in the Luttrell case above and they made reference to a number of cases. In R v. Turnbull the court classified eyewitness evidence in this category of unreliable evidence when they stated ‘whenever the case against an accused depends wholly or substantially on the correctness of one or more identifications of the accused which the defence alleges to be mistaken, the judge should warn the jury of the special need for caution before convicting’ . This decision has been followed in a number of cases such as R v. Forbes , Pringle v The Queen and R v Bailey .

In Benetto and Labrador v. The Queen the court classified ‘cell confession’ where in the words of the eminent Lord Hope ‘where an untried prisoner claims that a fellow untried prisoner confessed to him that he was guilty of the crime for which he was then being held in custody’ . In this case Lord Hope surveyed the general law on this issue and was quite firm that judges had a complete discretion to in their summing up to stress that certain types of evidence may be unreliable. The scope of this discretion is wide and merely bounded by the principles of Wedensbury reasonableness as laid out in Associated Provincial Picture Houses Ltd v Wednesbury Corpn . Lord Hope was mindful in Benetto that the judges did not want to lay any further restrictions on the discretion of judges. He did give a few examples of other cases where this discretion had been exercised by a judge such as in R v Makanjoula where the warning was to reliance solely on the uncorroborated evidence of a complainant in a sexual case or an accomplice.

It would appear then if we follow the Luttrell case that this unlimited nebulous discretion to warn a jury as to the reliability is our equivalent of the Daubert test on reliability. This is obviously unsatisfactory for a number of reasons; primarily the conundrum at the centre of expert evidence makes it very unsatisfactory. The use of a non-expert’s discretion in deciding which type of evidence is to be given an extra warning to the jury has obvious flaws. It also flows from the discretion of the judge rather than by presentation of a motion such as occurs in the U.S. Furthermore, it is doubtful whether this is the best model to use because the evidence could be completely unreliable or un-peer reviewed and, subject to the due diligence of counsel in the case, this may go undetected. The potential injustice of this is obvious and its terrible effects can be evinced by the Cannings case. This exact point has been eloquently expressed in the USA in the case of Barefoot v. Estelle :

‘In a capital case, the specious testimony of a psychiatrist, collared in the eyes of an impressionable jury by the inevitable untouchability of a medical specialist's words, equates with death itself’

It is easy to overstate these failings in the admissibility of new technology and idealise the American approach. The American system has similarly dealt with confusion in the application of the Daubert formula in particular the case of Kumho Tire v. Carmichael where the US Supreme Court had to consider the extents of the rule in Daubert and whether it covered non-scientific expertise.

The USA approach furthermore has highlighted a stark internally inconsistent part of judges deciding on reliability of evidence and the ultimate issue rule that we considered above. In the US case of Elsayed Mukhtar v. California State University, Hayward the US courts were considering the admission of expert evidence on racial discrimination in employment. There were a lot of issues within the case but for our purposes one of the most critical issues was regarding the interplay between the Daubert test of reliability and the exclusion of any testimony on the ultimate issue. The expert in that case had almost by definition to define whether discrimination had occurred because of the nature of his work, the way that the expert could avoid usurping the role of the jury was discussed by a higher court. They suggested that the way in which the evidence was delivered could be fundamental, very much like in the Doheny case, namely that the expert should concentrate his testimony on ‘general factors’. However, if the evidence was based overly on such factors then it was in danger of failing under the reliability tests imposed by Daubert which had to prove ‘the reasonableness of the expert's particular method of gathering and analyzing data in order to reach a conclusion on the particular matter to which his testimony was relevant.’ . The importance of this realisation is not limited to the inherent fallacies of US substantive law but appears to speak to a more fundamental tension.

The more enquiries and the more thorough that we require the evidence to be then correspondingly the more we must defer to the experts and allow them to give authoritative statements on the ultimate issue. This brings us back cyclically to considering the necessity of the Ultimate Issue rule, clearly many people disregard the rule as anachronistic dogma. However, it does have a solid theoretical basis: It is trial by judge and not by expert. The central conundrum to all this very amply highlighted here and will be expanded upon later in the conclusion section of this work. The unfortunate problem is that post-Cannings and in many modern academic work there is a definitive realisation that ‘The court has come late to an understanding that science is dynamic, with professional cultures influencing experimentation and interpretation in the natural sciences as in the social sciences’

The tripartite relationship between the Ultimate Issue rule, Reliability checks and the Contradiction of having non-experts overseeing experts combines to perhaps create an insoluble problem. A survey of the motivations behind these rules will perhaps exemplify why this is the case; there are competing motivations for the evidence to be of a high enough standard to be a reliable source, for the Judge and Jury to maintain their traditional roles and to allow the Criminal Justice System to protect itself from abuse from experts. The problem is that if the aspiration is to have the best evidence possible then there is an inevitable threat that as science progresses there must be an inevitable deference of the decision maker to the opinions of experts. There are tensions within the Criminal Justice System between impeding scientific progress and the danger of over reliance on such evidence. The recent miscarriages of justice have exemplified that there is a fine line between ‘recognition of the limits of scientific proof, and appearing unconvincing to a jury’ .Finally the person doing the balancing act between these competing concerns by definition is not an expert and must rely on the adversarial system to put all the relevant information at his disposal.
The phrases ‘frontiers of knowledge’ and ‘serious disagreement between reputable experts’ is suitably ambiguous and raises a number of issues over what the court is supposed to do with scientific evidence because this kind of evidence according to R v. Cannings is unsuitable for the courts. The approach here seems to beg a lot of questions such as can we truly call a science not at the frontiers of knowledge and challenging the orthodox views as such? Are judges then going to limit themselves to easy cases? The answers to these questions have no easy answers and unfortunately judges cannot shy away from this issue, it would be an equally great injustice on all those who would suffer but for expert evidence as to the truth of their allegations. If we then furthermore add into this mix the fact there are no substantive standards of reliability for the judiciary to turn to in English law other than those vaguely hinted at in Obiter dicta remarks from various courts we can start to comprehend why some commentators comment on the lack of principles and the incoherent approach of the English courts. The problem is that there is no concerted effort from academics or the legislature to come up with a coherent approach.

Furthermore given the criticisms of the approach in Doheny by people such as Evett we have to consider the usefulness of adopting the approach of altering the way in which juries are addressed as an overarching approach to novel expertise. Evett opines in relation to DNA evidence that the main problems are the proposed method of presenting Data should not be based on ever increasing probabilities of a match because they will become increasingly speculative. The criterion of the courts forces scientists to make sure they use the most rigorous of scientific procedures, the advocate should not try and give any guidance on this issue. It seems from all the cases that the main point of significance are that the expert uses classic methodology.

In the next section we will move onto discuss the conclusions that we can draw from the in-depth profile of expert evidence that we have presented above, we can hopefully draw together the strands that we have mentioned in all the sections above.

Conclusions

I started out this particular section by stating that the translation of principles to rules was a difficult one and that a concentration on this aspect of the exception for expert evidence would give us a better understanding of the concept. It is clear that when we look at the various issues that we have discussed such as ultimate issue, level of reliability, whether the information is in the public domain, peritus of the witness and the exceptions to hearsay that we see the law is hardly uni-vocal as respects experts.

The early courts relied on expert evidence purely because they did not have the expertise to understand the facts of a particular case. The need for experts in order to achieve any kind of justice is relatively straightforward . However, the Anglo-American jurisprudence on the law of evidence since the days of Gilbert has been concerned about the ‘best evidence’, this has manifested itself in the establishment of exclusionary rules of evidence. Holdsworth and Thayer both believed the exclusionary rules of evidence to have been a development that was fundamentally concerned with the jury and more specifically the protection thereof. An interesting section from Holdsworth illuminates one of the key factors which we see underpinning a lot of jurisprudence on the admissibility of expert evidence:

‘The rules of evidence, with which the law has been concerned all through its history, have never been solely dependant upon the doctrine of relevancy. They have never been solely dependant upon the logical doctrine of relevancy. Rather they assume the existence of these processes. They are concerned primarily with the selection of material on which these processes operate’

The rules on expert evidence exhibit a myriad of background principles which inform various parts of the rules. It is clear that the role of the jury as decision-maker is important when it comes to the formation of the rule of ultimate issue however the artificiality of such concepts makes that rule questionable. This is the tension between traditional jurisprudence about the law of evidence and the avoidance of artificiality and technicalities that slow down the administration of justice.

We saw how expert evidence is viewed as appropriate only in circumstances where the judge considers the jury members perhaps to not have enough experience to judge for themselves. This also seems tinged with concerns over the prejudicial effect that an expert stating his opinion on a matter which is within the capability of the jurors. The question over reliability however shows a greater laxity over the allowance of certain potentially unreliable evidence and seems to justify this by making a similar point to the one made about ultimate issue. However, clearly the same critique applies; surely a skilled advocate can bring an expert so close as to infer the expert’s opinion about the origin of a mark. It is for this reason that the House of Commons Science and Technology Committee produced a report dealing with the use of Science in the courtroom and recommended that there be a regulatory body that be setup to regulate ‘the forensic science market and provide independent and impartial advice on forensic science’ .

I mentioned in the introduction that following the prosecutions of people such as Angela Cannings and Sally Clark and their subsequent overturning, the judiciary ought to be more aware of the potential dangers of expert evidence. It is an oversimplification to encompass all the common law principles of expert evidence as being an inherent tension between the desire for a conviction to be based on the best possible evidence and the desire to avoid prejudicial effect by the voicing of unwarranted opinions. These two competing principles do underlie a lot of the approach that the courts take however from a jurisprudential standpoint the picture is more complex.

I think that the courts approach to the internal aspects of the exception to opinion evidence in relation to experts highlights a complete lack of holistic guiding principles and justifications. The contradiction at the centre of the expert evidence and current advocacy practice has combined so that the layered nature of the law of evidence is nowhere more visible than in expert evidence. The aims of the criminal justice system, the attributes of the adversarial system and the individual motives for procedural rules all combine to cause confusion. This is clearly the case if we consider but a few of the competing concerns that a court may have to balance. The criminal justice’s systems overriding concern is the establishment of guilt or innocence with respect for due process, fair trials, individual rights and a host of other concerns , There is a tension between these two fundamental principles. The adversarial system in itself believes that the method of having two competing parties is the best way to bring the whole truth to light. The exclusionary rules of evidence all have the same aim which is to protect the rational decision-maker from potentially unreliable or prejudicial evidence. The use of experts in the criminal justice system caters for and tends towards many of these values and traditions. It is clear that the identification evidence that we discussed above could potentially have a very large impact on the truth-finding value but the court was also keen to balance this against the perceived danger of the evidence being unreliable. This balancing act must also be carried out in a system which has many organisational pressures towards efficiency and quick decision making.

The competition between principles coupled with the inherent difficulty of non-experts trying to test the validity, truthfulness and reliability of experts is obvious:

‘Crank theories, invalid data and wholly unsubstantiated empirical claims have sometimes been accepted by judges or jurors, who have been hoodwinked by the terminology and trappings of legitimate science’

Furthermore, the pressure that is on valid experts to somewhat elaborate on their expertise can be intolerable at some points in the trial process. The example McConville & Wilson provide is that pathologists are commonly tempted to state the time of death with more precision than is scientifically valid . The ‘Prosecutor’s Fallacy’ we mentioned above is another example of experts straying outwith their realm of expertise. This was one of the major factors that Gross & Mnookin discussed in their study, namely that there has to be a considerable degree of scepticism applied to the expert that exhibits too much confidence, confidence and certainty are marketable traits and the expert evidence fees provide admirable rewards for those experts who are willing to exhibit such traits. This is not to say that these experts are charlatans or devoid of all benefit but that scientific method most often exhibits itself as the use of hypotheses based on the available facts. The pathology example is pertinent here and there are plenty of others such as in the US case of Zuchowiz where the scientist presented the cause of a heart failure as flowing from a drugs overdose as a fact when in scientific terms it wasn’t a scientific conclusion but a hypothesis of what caused death.

These problems are barely mentioned in any of the judgements on expert evidence, the few that I reported were part of limited sources, and is part of a general blindness of the legal profession to accommodate the advice derived from sociological studies. In my opinion the obsession with formal principles of truth, justice and due process can lead to a short sightedness to consider the full reality of expert evidence. The combination of these realisations with traditional theoretical models can build a better evidential system based on a mixture between sociological truths and theoretical principles.

I think that the internal incoherence of the rules on expert evidence is a direct result from competing principles and perhaps un-stated realisations of the flaws of the criminal justice system in dealing with experts. The importance for the legal profession of these realisations cannot be overstated and the dangers of expert evidence cannot be underestimated as was recognised in one of the most controversial prosecutions of recent years:

‘In a criminal case, it is simply not enough to be able to establish even a high probability of guilt. Unless we are sure of guilt the dreadful possibility always remains that a mother, already brutally scarred by the unexplained death or deaths of her babies, may find herself in prison for life for killing them when she should not be there at all. In our community, and in any civilised community, that is abhorrent’

The court there emphasised that there was a fine line to tread on one hand there is the desire not to impede science and ignore potentially very helpful evidence. On the other hand science which is at the frontiers of knowledge and very untested should not be given a role where the potential consequences of relying on such information are the abhorrence of wrongful convictions.

Hearsay & Its Relationship to Expert Evidence.

The exclusionary rules on opinion and the exclusionary rule of hearsay are very similar and flow from similar concerns. Hearsay is basically the prohibition on the repetition of non-formal statements by a third party from a witness. That means that if somebody is at a crime scene and overhears someone else making a comment, the subject of which becomes pertinent at a later date, then there is a rule against the repetition of that third party statement in order to evince whatever the subject matter of the particular comment was. The rationale for the rule was stated by Lord Bridge in R v. Blastland :

‘Hearsay evidence is not excluded because it has no logically probative value…The rationale of excluding it as inadmissible, rooted as it is in the system of trial by jury, is a recognition of the great difficulty…of assessing what, if any, weight can properly be given to a statement by a person whom the jury have not seen or heard and who has not been subject to any test of reliability’

Reliability is highlighted again here as the dominating concern of the rule, the fear that the evidence may be unreliable or prejudicial is the motivating fear for the existence of the rule. An interesting story about the origin of the test will also highlight the exact nature of the exclusionary rule. In 1603 Sir Walter Raleigh was convicted of high treason on the basis that a witness had overheard someone saying that they overheard Walter Raleigh saying he would slit the monarch’s throat. The abhorrence, and complete leap of the evidential gap with absolutely no reliability, that this trial was viewed with by jurists caused the formulation of a rule against such evidence .

There is obvious problem that presents itself in relation to experts when we consider the hearsay rule and the expert’s evidence. The expert will very often base his opinion on the description of certain facts by a third party, sometimes those statements by a third party will constitute hearsay statements and as such undermine the whole of the experts testimony and make it inadmissible. Furthermore they are almost inevitably going to have reference to academic works written by third parties which would fall under the strict ambit of the hearsay rule. The Law Commission came to consider these issues in detail in their report on Hearsay which was largely embodied in the Criminal Justice Act 2003 .

This situation arose in the case of R v. Steven Abadom where the court considered in depth whether such evidence should be admissible. The court completely rejected any argument that because the expert in that case hadn’t compiled the Home Office statistics upon which he based his work that any evidence was inadmissible as hearsay. The court completely rejected this and stated ‘it seems to us that the process of taking account of information stemming from the work of others in the same field is an essential ingredient of the nature of expert evidence’ . They did however state that there were two caveats to this rule which were that following English Exporters v. Eldonwall that any fact upon which the expert relies has to be admissible in itself. The second application of the hearsay rule that Abadon referred to was that ‘where the existence or non-existence of some fact is in issue, a report made by an expert who is not called as a witness is not admissible as evidence of that fact merely by the production of the report, even though it was made by an expert’ .

The distinctions made in Abadon were discussed in the Law Commission paper. They divided the hearsay exceptions for expert evidence as being threefold. The first exception is ‘knowledge which forms part of the expert’s professional expertise, although not acquired through personal experience’ . The example pointed to was that of Borowski v Quayle where reference to a standard pharmaceutical handbook was made by an expert. The second exception was to allow hearsay statements that ‘draw on technical information widely used by members of the expert’s profession and regarded as reliable’ . In Rowley v London and North West Railway the court allowed evidence as to the average life span of people as based on standardised Actuarial tables. The third exception relates to a statutory exception contained within s.30 of the Criminal Justice Act 1988. This allows for an expert to prepare a report and any fact or opinion in that report may be adduced as evidence as if the person preparing the report had given it in oral evidence. It is a strange rule and requires the courts leave and as the law commission stated ‘but we would regard it as extremely unlikely that the courts would allow an expert report to be adduced without calling the maker if the opposing party had a genuine wish to cross-examine on it’

The problem perceived by the Law Commission was that these exceptions to hearsay were restrictive, the law still remained as stated by R v. Turner where Lawton LJ demarcated the border between admissible expert hearsay and that which is excluded:

“It is not for this court to instruct psychiatrists how to draft their reports, but those who call psychiatrists as witnesses should remember that the facts upon which they base their opinions must be proved by admissible evidence. This elementary principle is frequently overlooked”

The vexatious results of this approach were highlighted in the case of R v. Terry Jackson where a piece of evidence that was in the statements made under the Criminal Justice Act 1967 but were never lodged as evidence at trial or proved in examination of the accused. This meant that the whole of the expert’s DNA evidence was wholly inadmissible because certain facts upon which his assertion was based were considered to be primary which rendered the evidence inadmissible. The judiciary were highly critical in that case of all involved when they stated ‘if inexperience accounts for much of the foregoing, we can but hope that this case and these comments serve rapidly to offset such’ . It is clear that the mistake had caused a number of days of wasted time and money for both the parties involved and the jury. The main problem that was identified by both the Law Commission and the Royal Commission on Criminal Justice was that an offender could require an expert to call all the assistants who carried out routine calculations and tests upon which his evidence was primarily based. The clear dilemma for the Law Commission was between the time and expense of the rule, which was potentially so high as to make it prohibitive, and the rights of the accused to challenge evidence by cross examination. They considered a number of options such as charging costs of doing this to the opposing parties, creating a blanket exception to hearsay and ones that were varyingly based on judicial discretion.

This situation was revisited by the Criminal Justice Act 2003. s.127 of the CJA 2003 dealt with this exact question. It deliberately overrules the points that Abadon made in reference to primary facts and allows that provided it is in the interests of justice then expert advice maybe premised upon hearsay statements. The factors that have to be considered in relation to the making of an order under s.127 are the expense of calling the person making the original report, whether that third party could give any more relevant advice than the expert at hand and whether that person can be reasonably expected to remember all the facts to a sufficient degree. This is very close to the suggestions made by the Law Commission and is probably premised on the general attitude to hearsay under the new regime.

The reason for this change has a lot to do with the attitude that the legislature was taking with the whole rule of hearsay which in some respects was being seen as far too restrictive. The government weren’t quite as radical as to accept the proposals of Lord Justice Woolf, which were cited in the passage of the CJA 2003 through parliament, which suggested abolition of the hearsay rule and reliance on judicial discretion. They preferred to follow the more staid advice of the Law Commission. The main aims of the Law Commission were not radical overhaul but the avoidance of what they saw as a particularistic system that exhibited no coherence and a chronic amount of complexity. The wasted time and lack of cogency in the application of the rule were the main criticisms. The aim was therefore simplification and consideration of the level of exclusion was undoubtedly influenced by the fact that ‘Cogent evidence may be kept from the court, however much it may exonerate or incriminate the accused, because the fact-finders are not trusted to treat untested evidence with the caution it deserves’. They weren’t abolitionist in any sense, in fact they specifically rejected this approach, however they were in favour of considerable loosening of the rule and increasing of judicial discretion. The CJA 2003 thus took the format that all hearsay was inadmissible apart from specific exceptions and included limited judicial discretion. Section 127 embodies these principles in min-version. The expert evidence is prima facie inadmissible unless it is in the interests of justice that the evidence be admitted. The interest for our purposes in this section of the work is that the approach mandated by the legislature is particularly liberal and gives as wide a possible interpretation to the exception.

The debate over Hearsay exemplifies again this dominant tension in the mind of the courts between the discovery of the truth and thus not losing cogent evidence and the potential dangers of including such evidence given its potential unreliability. The concerns are slightly distinct but very similar to the opinion evidence principles that we discussed in the previous section which by and large cover a lot more ground than does the hearsay provisions. An expert witness must give evidence in the form of an opinion however that evidence might include hearsay remarks but needn’t necessarily. The degree of attention that has been lavished on the hearsay aspects has not been replicated in the opinion part of expert evidence. The tensions that we identified in the first section regarding concerns over the reliability of the evidence are replicated here. The concerns expressed by the courts over things such as opinion on the ultimate issue and the approach it takes to novel sciences and technology generally exhibit a concern predominantly over the fact that undue reliance may be placed on potentially unreliable evidence.

The conclusions that we can derive from the changes in the Criminal Justice Act 2003 are probably limited. There is a definite movement towards a more inclusive approach to hearsay evidence, the principles that this change is being guided by are far from clear however we will discuss that in the following section. The interesting observation that we can take from the change is that in the responses to the Law Commission there was a considerable divide within the judiciary respondents between the various direction that hearsay evidence ought to take. This shows that perhaps the reason for the incoherent approach to opinion evidence that we saw exhibited in the first section is due to judicial attitudes towards the ability of both judge and jury as decision-makers to evaluate the weight of different kinds of evidence. It is also not to be assumed that this kind of attitude is novel or revolutionary, Jeremy Bentham, nearly two centuries ago, advocated abolition of all rules of evidence and specifically stated that ‘in every case by exclusion, misdecision for want of evidence is more likely to be produced, than by admission, misdecison through deception and by means of evidence’ and he continued on to state ‘The theorem is this: that, merely with a view to rectitude of decision, to the avoidance of the mischief’s attached to undue decision, no species of evidence whatsoever...ought to be excluded’

Overall Conclusions

This work has attempted to analytically assess the admissibility and exclusion of expert evidence in criminal trials. This was to be done with a critical bent and we must recognise that in doing this and criticising the various areas and principles of expert evidence it is for us then to suggest tentatively some conclusions. However, before I move onto to the exact solutions and answers that I would suggest it is as well to be aware that a work such as this can never come up with entire solutions. The main contribution of this work has been to get all the issues on the same page. I have drawn on a wide range of sources that all discuss each of the issues in minute detail. The only place where one finds all these issues covered is in the textbooks and they’re glossed over. I could not find any holistic articles on expert evidence. The foregoing discussion has amply proven one fact: there is a great deal of confusion and a number of informal standards being applied in the administration of justice.

I started this work with a simplistic statement which is a classic allegory for the whole of the law of evidence and that is the spectre of Judge Bridlegoose who rolls dice to decide cases. The law has to ‘get it right’ more than 50% of the time and a fundamental part of this is adjective law. Adjective law subsumes all procedural laws that govern the use and administration of substantive laws. Expert evidence is but one small part of this but nevertheless it is subject to the same criteria, it’s use must be helpful to the legal sphere otherwise we have not progressed from rolling a dice or armed combat to decided cases. In fact for rules concerning the admissibility of expert evidence we ought to consider it as more pertinent given that it forms an exception to two of the largest exclusionary rules of our system of evidence.

I want to start from the obvious and go from there in coming to concrete conclusions. The law cannot work in a scientific vacuum, we must inevitably rely on experts as a source of evidence, this raises instantly all the problems that we have discussed above regarding how compatible the approach is with the rules and principles informing evidence procedure and in fact the whole criminal justice system. In my opinion this fundamental incompatibility cannot be reconciled and the two disciplines of science and law will always be at odds. The contradiction of non-experts presiding over experts is I would suggest insoluble and continual reference to the issue does not help. The fundamental point here, which also deals with the ultimate issue rule, is that the test ought to be one of deference and education. The balance between these depending directly on principles of reliability. This would help create an inter-connected system that places primacy on the reliability of expert evidence. Furthermore, we have to shed ourselves of our positivist mindset that law must be perfect because social science work on all areas of law have highlighted that legal actors are susceptible to bias and make mistakes of judgement. The question for law academics is not to point out how this exhibits itself in individual cases and how to deal with certain sciences but to deal with the problem holistically.

The subject matter of expert evidence has to start us on a reconsideration of all our fundamental principles. The exclusionary system is premised on the existence of the jury and thus the overriding concern has to be avoiding the placement of unreliable evidence in front of the jury decision-makers. I am not going here into issues that discuss the level of understanding that they may or may not comprehend because that is a matter of degree. In my opinion there are thus two fundamental aspects that go towards that principle and that is the question of reliability of evidence and the role of the expert witness. These two issues are unsurprisingly the two areas that I devoted the most time to because I think that these exhibit the crux of the issue. The role of an expert witness is a difficult problem, undoubtedly the countless judicial and legislative statements to the effect that expert witnesses ought to be independent and give unbiased opinions are not having the desired effect because in both civil and criminal cases there are still plenty of incidences, as the case of Cala Homes and the unfortunate article by Mr Goodall show, where experts are still succumbing to the adversarial bias.

However, this is not through a deliberate mendacity on the part of experts but is a by-product of the criminal justice system and to a lesser extent the civil justice system. The conundrum between scientific uncertainty and the adversarial bias is a difficult problem here as well. On the one hand the more courts try and look for experts to come to a unanimous decision or at least agreement on core principles then the more alienated that advice becomes from true science which may have numerous competing theories of hypotheses on a particular subject matter. On the other hand the adversarial scientist has not only the tendency but the opportunity to mislead the court as to a particular viewpoint. The choice between these two situations is difficult and inevitably each legal system will choose its own balance between the two situations. In my opinion the use of adversarial witnesses is by far the best, the adversarial situation may produce bitterly opposing views but most times there will be some common ground between the parties as Bracewell J correctly identified in Manchester City Council v. B. The adversarial system is our chosen method of prosecuting people and seeking redress within our society, we cannot then bemoan the failings of that system in favour of another because a certain type of evidence doesn’t fit the mould. The likelihood of defence witnesses to present a one-sided story is inevitability in relation to fact evidence; there are certainly not many articles about the potential injustice of the jury paying attention to that evidence. Perhaps it is our general paranoia within the legal community of unreliable evidence that causes to take this reaction but in my view it is unwarranted. It maybe criticised that perhaps a jury will put more weight on a scientists view but then if they have competing scientists then it comes down to who they find more believable in all the circumstances. It may be further criticised that the jury will be choosing between two opinions wholly alienated from medical opinion, the judge is their as an arbiter to catch the worst excesses and in any case in a trial many of the facts will be based on a narrative from a witness based on events that occurred months if not years ago: how removed from reality are those facts?

The conclusion of my work is that the problems facing expert evidence are a result of incompatibility between competing ideals within the law of evidence as general. We have to accept that no model will suit all principles and that nothing will ever be perfect, we must merely prioritise which values will most promote rectitude of decision and these, for me, must be reliability, adversity, deference and education.

Bibliography

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Baskind, E The Expert Witness in England & Wales: 2001 IRLCT 229
The End of the ‘Hired Gun’? An English
Perspective
Caldwell, P Courting the expert: a clash of culture? 2005 BJH 730

Davies, G Expert Evidence: Court Appointed Experts 2004 CJQ 367

Davoli, J Psychiatric Evidence On Trial 2003 SMULR 56

Dyson, D Expert testimony and “subtle discrimination” in 2004 GGULR 34
the workplace: Do we now need a weatherman to
know which way the wind blows?

Evett, I Dna Profiling: A Discussion Of Issues Relating To 2000 CLR 341
The Reporting Of Very Small Match Probabilities

Gillespie, L Expert Evidence and Credibility 2005 SLT 53

House of Forensic Science on Trial 7th Report 04-05
Commons
Science and
Technology
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Jackson, C The Uses And Abuses Of Experts And 2000 JPIL 19
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Kovera, M, Assessment Of The Commonsense Psychology 2002 PPPL 180
Russano, M & Underlying Daubert Legal Decision Makers’
McAuliff, B Abilities To Evaluate Expert Evidence In
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Law Evidence In Criminal Proceedings: Hearsay LC245
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Meintjes- Ruling On Expert Evidence In South Africa: 2001 IJEP 226
Van der Walt A Comparative Analysis

Mnookin, J & Expert Information and Expert Evidence: 2003 SetonHLR
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Decisions Highlight The Tensions

Roberts, P Towards The Principled Reception Of Expert 2004 IJEP 215
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Online Resources

Bailii – www.bailii.org
LexisNexis – www.lexisnexis.com
Westlaw – www.westlaw.co.uk
Expert Witness Institute – www.ewi.org.uk
Parliamentary Office of Science & Technology Publication No.245 (2005) ‘Science in Court’ - http://www.parliament.uk/documents/upload/postpn248.pdf.
Online Lecture Notes - https://www.kent.ac.uk/law/undergraduate/modules/evidence/expert_evidence.htm

Please note: The above essays and dissertations were written by students and then submitted to us to display and help others. Thanks to all the students who have submitted their work to us.

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