Expert Opinion Evidence in the UK - Literature review Example

Expert Opinion Evidence in the UK Introduction The common law of England had been ambivalent towards expert testimony. As such, it had not considered the contemporary use of such evidence. At that juncture, the emphasis of the common law had been upon the possession of first-hand knowledge by the person making the testimony. As a consequence, expert testimony would have been inadmissible, ab initio[Len09]. However, with the passage of time, the courts admitted an exception to the first-hand knowledge requirement and admitted the expert opinion of skilled witnesses as evidence. Albeit, the expert witness would be devoid of first-hand knowledge, such witness would testify with the sole objective of assisting the court. The latter would, thereafter, instruct the jury regarding the information provided by the expert witness[Len09]. As such, the system of admitting expert witness evidence and permitting such witnesses to testify before the jury, directly, was permitted by the courts, during the latter half of the 18th century. Such testimony pertained to a category of facts about which the expert witnesses alone, could be expected to have information. Such evidence assisted the jury and provided supplementary information regarding the question to be determined by the jury[Len09]. Nevertheless, with regard to expert evidence, the common law has been entertaining a longstanding debate. This pertains to the extent to which the law should demand a demonstration of a field of expertise or accept a specific discipline or some other requirement as a condition for the admissibility of expert opinion on a matter. The uniform evidence legislation does not incorporate such explicit requirements. However, it makes the demonstration of specialised knowledge, prior to submitting expert opinion, as evidence, mandatory[Aus145]. The query, as to whether there is an area of expertise regarding which an expert in that field may furnish evidence, has come to the fore, in the context of fingerprinting evidence, use of seat belts, reasons behind traffic accidents, voice identification, employment of polygraphs, and DNA profiling. The expert witness has to be qualified by training or practical experience in some area of knowledge. Such knowledge should be beyond the knowledge at the disposal of the trier of fact[Aus145]. Moreover, this knowledge should be of assistance to the trier of fact. For example, the subject matter of Dasareef Pty Ltd v Hawchar was the submission of an appeal to the High Court of Australia, regarding the admission of an expert’s opinion as evidence. The appellant raised the query, whether the following conditions were required under the law, for admitting expert testimony. First, identification of the facts assumed, underlying the opinion. Second, establishing these assumptions by the admissible evidence. Third, disclosure of the rationalé behind the conclusions of the expert[Ham11].This query was not provided with a direct answer by the court, which opined that admissibility of the expert evidence was to be determined by the language of the relevant legal provisions. As such, this important question of evidence law remained unresolved. With regard to resolving disputes pertaining to factual issues, it has been persistently conceded that specialised fields of knowledge have to be explained to the jury by the experts in that particular area of knowledge. This perception is based upon the fact that in the majority of the cases, the jury can be assumed to be unfamiliar with such knowledge[The112]. In addition, the provision of expert opinion prevents the jury from arriving at incorrect inferences from the evidence presented in the court. Moreover, such expert evidence enables the jury to assess the importance to be attached to the evidence that pertains to the expert opinion. Thus, it has become commonplace for witnesses with sufficient expertise to submit expert opinion in the courts, upon factual matters that are encompassed by their specialisation, with a view to assist or guide the jury in resolving contested factual issues [The112]. With regard to criminal proceedings, it has been observed that on occasion, it is mandatory to include expert evidence. From the theoretical point of view, the purpose of expert evidence is to merely educate the jury. In other words, the expert witness enlightens the jury about the relevant areas of their expertise and knowledge, so that the jury can competently evaluate the evidence requiring such expert knowledge. Such a course of action relates to the comparatively less intricate areas of specialised knowledge[The112]. With regard to cases, wherein the field of expertise is especially difficult to understand, the jury may defer to the knowledge and opinion of the expert. This is with regard to the resolution of the disputed factual issue to which the expertise relates. Consequently, the opinion provided by an expert witness can be exceptionally influential. This is in the context of the assistance that such opinion can furnish to the jury. As such, the intricacy of the area of knowledge involved, will determine the extent to which the evidence of the expert will be convincing[The112]. Moreover, this complexity determines the degree to which the jury could be expected to accept this opinion, without endeavouring to form its own opinion. When the reliability of the expert evidence is incontrovertible, then considerable benefit is to be derived. This is due to the reality that it would be unfeasible to provide the jury with adequate expertise of its own, with a view to circumvent deference on its part. Nevertheless, deference by the jury in complex fields of knowledge can prove to be dangerous, in the presence of legitimate apprehensions regarding the reliability of the evidence given by the expert[The112]. Some of the reasons for being circumspect regarding expert evidence are described in the following. First, the field of knowledge of the expert could be a new or developing science. This area could be devoid of peer reviews or there could be misgivings regarding the validity of the methodology, assumptions or conjectures adopted by the expert. Secondly, it may not be possible to locate another expert in the same field. This would make it impossible for the opposing party to effectively criticise the expert evidence. Thirdly, in such instances, the jury could be obliged to defer to the view of the expert, despite the absence of adequate reliability of the latter’s evidence[The112]. Moreover, the expert evidence could even be unreliable to the extent that it would warrant outright rejection. Fourthly, some of the participants in the criminal trial process could possess an inadequate understanding regarding the limitations of the expert evidence. Such individuals could even presume that the presentation of the expert opinion as scientific evidence denoted its reliability. In several trials, it was noticed that the jury had found it very difficult to follow the cross-examination that had endeavoured to highlight the flaws in the scientific methodology adopted by the expert testimony[The112]. In addition, a number of recent decisions have made it clear that expert evidence poses a problem that cannot be ignored. In many instances, such evidence is admitted without much reservation. This has resulted in several cases of wrongful acquittals and wrongful convictions[Dur111]. For example, an individual had been convicted for murder, on the basis of expert evidence related to an earprint. Subsequently, a retrial had been conducted, in which the expert evidence leading to his conviction was demonstrated to be defective. In this case, Dallagher had been convicted of murder, on the basis of earprint evidence. He was convicted of having murdered Dorothy Woods, after a DNA analysis of the earprints left at the scene of the crime, were interpreted by an expert as belonging to him. This expert had claimed at trial that the earprints had been made by the accused, and that he was absolutely convinced about this[ONe04]. Furthermore, in several cases, it was noticed that the jury cannot be relied upon to arrive at a correct decision, if their comprehension of the facts is distorted by the evidence given by an expert witness. For example, in Clark (Sally) (No. 2), the defendant was accused of having murdered her infant sons. The case was dismissed, as the prosecution’s expert witness failed to disclose test results for one of the diseased sons. Moreover, the prosecution expert presented fallacious statistical evidence and claimed that the deaths had a very low probability, namely that of 1 in 73 million, of taking place[Sal14]. Reliance upon this expert’s evidence would have resulted in a serious travesty of justice. In addition, in Cannings, the Court of Appeal set aside the defendant’s conviction for murder of her infant sons. The Court ruled that two or more unexplained infant deaths in the same family did not lead to the conclusion that murder had transpired. New evidence presented to the Court disclosed that multiple cot deaths in a family could be attributed to genetic reasons. Moreover, a report submitted to the Court made it clear that a second cot death in the family was usually on account of some natural cause[The112]. In Harris and others, the generally conceded medical opinion that a non-accidental injury to the head of an infant could be inferred from the mere presence of a specific form of intra-cranial injuries, was refuted by the discovery of new evidence. Furthermore, in Luttrell, the Court of Appeal set aside the proposition that expert evidence could be admitted only when the methods employed were adequately described to be tested in cross-examination, and verified or falsified[The112]. All the same, it was accepted that the trial judge could consider methodology at the time of accepting or rejecting prosecution expert evidence, under the provisions of Section 78(1) of the Police and Criminal Evidence Act 1984. Furthermore, the Court of Appeal affirmed that expert evidence could be discarded on the grounds of possessing probative force that was sufficiently insignificant to influence a decision[The112]. As such, in England and Wales, admissibility criteria for evidence relate to relevance and reliability. There are several tests that establish the reliability of the evidence and the conclusions drawn from it. These tests include; presence of general acceptance of the evidence; the basis of the evidence should be specialised knowledge, experience, education, training, or skill; it should have been published and peer reviewed; the application has to be relevant and should produce justifiable conclusions; and the evidence should be based on scientific validity and adequate data[Mal14]. The extent to which importance and certainty are attached to scientific evidence is especially significant with regard to a new technique that is still in the developmental stage, and where it is apprehended that the technique has to be subjected to additional tests and evaluations, prior to being adapted to forensic application. The forensic methods tend to be quite diverse. As a consequence, the practitioners could be functioning on a case-led basis [Mal14]. This would produce analyses that defy verification by standardised procedures. For instance, in R v Stamford, it was to be ascertained whether an article was obscene or indecent. The defence made an application to the court, seeking expert opinion to describe and differentiate these terms. This was rejected summarily by the court, which opined that these terms denoted moral judgment. Such judgment was best undertaken by a jury, rather than an expert witness[Rob101]. The court emphasised that contemporary moral and ethical norms were best expressed by juries. Conclusion As such, there have been several instances, wherein expert testimony relating to the essentials of the offence has been tantamount to the arrogation of the investigatory prerogative of the jury and the court. English law does not incorporate a general formal obligation that the testimony of a witness has to be validated. The principal difficulty that arises from expert testimony is the fact that final judgment may not be attained on the basis of the normative standards determined by the jury. Usurpation becomes a tangible threat in situations where specialist expertise and reasonable expectations are diametrically opposed to each other. As such, political morality determines whether community norms, as represented by the jurors in court, are to be superseded by expert technical criteria. References Australian Law Reform Commission, n.d. The Opinion Rule and its Exceptions. [online] Available at: [Accessed 11 November 2014]. Cannings (2004) EWCA Crim 1. Clark (Sally) (No. 2) (2003) EWCA Crim 1020. Dasareef Pty Ltd v Hawchar (2011) HCA 21. Durston, G., 2011. Evidence: Text & Materials. 2 ed. Oxford, UK: Oxford University Press. Hamer, D., 2011. 21st Century Challenges in Evidence Law. The Sydney Law Review, 33(3), pp. 325-332. Harris and others (2005) EWCA Crim. Lens, J. W., 2009. The (Overlooked) Consequence of Easing the Prohibition of Expert Legal Testimony in Professional Negligence Claims. University of Louisville Law Review, 48(1), pp. 53-94. Luttrell (2004) EWCA Crim 1344. Mallett, X., Blythe, T. & Berry, R., 2014. Advances in Forensic Human Identification. Boca Raton, FL, USA: CRC Press. O'Neill, S., 2004. Expert evidence flaws clear 'earprint killer'. [online] Available at: [Accessed 14 November 2014]. Police and Criminal Evidence Act (c.60), 1984. London, UK: Her Majesty's Stationery Office. Roberts, P. & Zuckerman, A., 2010. Criminal Evidence. 2 ed. Oxford, UK: Oxford University Press. Sallavaci, O., 2014. The Impact of Scientific Evidence on the Criminal Trial: The Case of DNA Evidence. Abingdon, Oxon, UK: Routledge. The Law Commission, 2011. The Admissibility of Expert Evidence in Criminal Proceedings in England and Wales. [online] Available at: [Accessed 14 November 2014]. Read More