The Expert Witness, Forensic Science, and the Criminal Justice Systems of the UK

S. Lucina Hackman, Fiona Raitt, Sue Black, S. Lucina Hackman, Fiona Raitt, Sue Black

• Publisher: CRC Press
• Year: 2019
• ISBN:
  9781315354392
• Edition: 1
• Topic: Law
• Subtopic: Criminal Law
• Index: Law

The global nature of crime often requires expert witnesses to work and present their conclusions in courts outside their home jurisdiction with the corresponding need for them to have an understanding of the different structures and systems operating in other jurisdictions. This book will be a resource for UK professionals, as well as those from overseas testifying internationally, as to the workings of all UK jurisdictions. It also will help researchers and students to better understand the UK legal system.

Ethics and the Role of the Expert Witness 1

Tony Ward

Contents

1.1 Fidelity and Trust

1.2 Ethics and the Criminal Procedure Rules

1.3 Keeping within One’s Expertise

1.4 Integrity, Objectivity and Impartiality

1.5 Transparency and the Adversarial Process

Notes

References

The ethical obligations of a witness called upon to give expert opinion evidence are more complex than just telling ‘the truth, the whole truth and nothing but the truth’. Indeed, one of the traditional legal objections to opinion evidence – evidence about the inferences a witness draws from facts – is that dishonest opinion evidence would escape the law of perjury. ¹ The main theme of this chapter is that as well as being truthful, experts have an obligation to express justified opinions and to make the facts, assumptions and methods on which those opinions are based as transparent as possible. These obligations are inherent in the role that the expert witness voluntarily accepts (it is rare for an expert to testify under compulsion). They also reflect the obligation in the Code of Conduct for Forensic Practitioners (Forensic Science Regulator 2017) to ‘act with honesty, integrity, objectivity and impartiality’.

It is mainly the judges who authoritatively define what is expected of an expert witness, and nowadays in England and Wales – though not to the same extent in Scotland – these expectations are largely codified in the Criminal Procedure Rules (Crim PR) as well as the guidance contained in some leading judgements. In accepting the role of an expert witness, a practitioner incurs a prima facie obligation to meet those legally defined obligations, and thus law is often an important guide to ethics (Willis 2009). On the other hand, legal guidance should be interpreted as far as possible so that it makes good ethical sense.

1.1 Fidelity and Trust

The moral philosopher W. D. Ross brought telling the truth and keeping explicit or implicit promises together as a category of prima facie ‘duties of fidelity’ (Ross 2002: 21). The maker of an ostensibly factual communication gives an implicit assurance that it is true (Moran 2006), and the duty to honour this assurance by telling the truth is an aspect of the duty to keep promises. Duties of fidelity in Ross’s sense make up most of the ethical obligations of an expert witness.

An expert witness – and particularly a forensic scientist – is relied upon by the court to examine certain evidence and draw inferences from it that the court could not draw for itself. The epistemic dependence of the court on the expert creates special responsibilities. Joseph Sanders argues that the central duty of the expert is to hold and express justified beliefs:

When we say that we believe something to be true, we are warranting our commitment to the truth of a proposition (the belief condition) and that we are entitled to this belief (the justification condition). … It is irresponsible to assert knowledge without adequate justification. Behavior that is irresponsible in this way is unethical when it occurs within settings where individuals hold themselves (and their representatives) out as having knowledge upon which others rely. It is unethical for expert witnesses to hold or express unjustified beliefs.

(Sanders 2007: 1541–2)

Sanders’s view raises a thorny philosophical issue about whether people have the sort of voluntary control over their beliefs that is necessary for moral responsibility (Steup 2001), and it seems to erase the distinction between acting unethically and making an honest mistake. Rather than being ethically obliged to hold only justified beliefs, experts have a duty to follow practices of inquiry that ensure, as far as is reasonably practicable, that they form only justified beliefs. Thus, they should examine all – and only – the available evidence relevant to their task, analyse it conscientiously and impartially, and do their best to avoid perceptual, logical or mathematical errors. In Steven Lubet’s view, the ‘single most important obligation of an expert witness is to approach each question with independence and objectivity’ (Lubet 1999: 467).

Because of the epistemic dependence of courts, and laypeople in general, on experts, relations between them ‘rest on an ineluctable element of trust’ (Hardwig 1994: 89). Experts must not abuse the trust placed in them and must not ‘undermine the attempts of laypersons to be rational’ (Ibid: 90). In short, experts must be trustworthy. But in the case of expert witnesses, that trustworthiness must be of a particular kind.

Paul Faulkner (2011) has distinguished between two kinds of trust which he terms ‘predictive’ and ‘affective’. Predictive trust involves relying on someone to do what we have some inductive reason for thinking they are likely to do. For example, I may trust someone to give me good advice if they have often given me good advice about similar matters in the past. Affective trust, on the other hand, goes beyond what one has inductive reasons to expect, and is bestowed because it is appropriate to relationships characterised by norms of trust. For example, I tend to believe what my students tell me about their reasons for missing classes because it would undermine the relationship between us if I constantly doubted their word (and because the truth or otherwise of their excuses is relatively unimportant). I run a risk of being deceived, but a risk that I judge to be acceptable. Ordinary social relationships are characterised by reciprocal expectations that one party will tell the truth and the other will believe them, unless there is some particular reason to doubt them. But relations between witnesses and fact-finders are not like that.

This is especially true in the case of prosecution witnesses testifying in a criminal trial. The jury’s duty is to acquit the defendant unless the evidence makes them sure of guilt (subject to certain exceptions where the burden of proof is placed on the defence). Jurors do not have the sort of relationship with experts in which the expert has an expectation of being believed simply on the strength of her implicit assurance that what she says is correct. Nor are they entitled to take the risks inherent in affective trust when those risks will be borne by the defendant rather than themselves. The jury, therefore, should not believe the expert unless they have good positive reasons to believe that what the expert says is true, and experts should not try to persuade juries to have greater confidence in their opinions than is warranted by the evidence of the experts’ reliability. The relation between a witness and the jury lacks the reciprocity of trust to be found in ordinary social relationships: the witness has a strong obligation to tell the truth, without any legitimate expectation that the jury will take her word for it. This is true not just of experts but of all witnesses, and is one reason why giving evidence is often a distressing experience for ordinary witnesses, and why the court is sometimes experienced by experts as a site of ‘institutionalized pure mistrust’ (Wynne 1989: 33).

Experts who are skilled witnesses may be able to overcome this mistrust through their ability to develop a rapport with the jury. But trial outcomes should not be determined by which expert has the greater ‘charisma’ or the better ‘chemistry’ with the jury (House of Commons 2005: paras. 140–2). The proverbially effective courtroom performances of the pathologist Sir Bernard Spilsbury, coupled with his often unjustifiably dogmatic opinions, now appear highly suspect from an ethical point of view (Rose 2007).

The responsibility of experts is not to persuade juries to trust them, but rather to provide the juries with the evidence on which to base an independent judgement of how far to trust them. This is made explicit in the famous Scottish case (often cited in the English courts) of Davie v Edinburgh Corporation 1952 SLT 54:

Their duty is to furnish the Judge or jury with the necessary scientific criteria for testing the accuracy of their conclusions, so as to enable the Judge or jury to form their own independent judgment by the application of these criteria to the facts proved in evidence. … The bare ipse dixit of a scientist, however eminent, upon the issue in controversy, will normally carry little weight, for it cannot be tested by cross-examination nor independently appraised, and the parties have invoked the decision of a judicial tribunal and not an oracular pronouncement by an expert.

(p. 57)

The same principle is encapsulated in a more recent Scottish judgement: the evidence ‘must follow a developed methodology which is explicable and open to possible challenge, and it must produce a result which is capable of being assessed and given more or less weight in light of all the evidence before the finder of fact’. ² An ‘ethical habit’ of ‘transparency’ (Candilis et al. 2007: 17) should lead experts to explain their reasoning in such a way as to facilitate these processes of challenge and assessment.

1.2 Ethics and the Criminal Procedure Rules

The ethical duty of transparency is made explicit in the (English) Criminal Procedure Rules 2015 (Crim PR), r. 19.4, which stipulates the contents of an expert’s report. Among other requirements, the report must:

• (f) where there is a range of opinion on the matters dealt with in the report—
• (i) summarise the range of opinion, and
• (ii) give reasons for the expert’s own opinion;
• (g) if the expert is not able to give an opinion without qualification, state the qualification.

Although no equivalent rules exist in Scotland, the courts appear to have similar expectations. In Wilson v HMA (2009) HCJAC 58 the Appeal Court endorsed the guidance set out in The Ikarian Reefer (1993) 2 Lloyd’s Rep 68, the source of many of the principles now contained in the Crim PR. The forensic anthropologists who testified in HMA v Hainey (2013) HCJAC 47 were criticised for ‘refrain[ing] from making any reference to apparently respectable scientific writing in the field which had the effect of seriously qualifying their views’ (para. 50), as they would have been required to do in England by both Crim PR r. 19.4(f) and (g). In any case, transparency about such matters is a clear ethical obligation. An expert speaks with the authority of a particular profession or branch of knowledge and where no contrary indication is given may reasonably be assumed to speak for that profession or branch of knowledge as a whole. It is misleading and therefore unethical to give that impression where the community of experts is in fact divided (Hardwig 1994: 92).

An additional requirement of Crim PR 19.4, first introduced in 2014, is that a report must

(h) include such information as the ...

Table of contents

• Cover
• Half-Title
• Title
• Copyright
• Contents
• Preface
• Acknowledgements
• Editors
• Contributors
• Introduction
• 1 Ethics and the Role of the Expert Witness
• 2 The Impact of Case Law and Inquiries on the Role of the Expert Witness
• 3 Miscarriages of Justice and the Role of the Expert Witness
• 4 Expert Evidence in Scotland in Criminal Trials
• 5 The Role of the Expert Witness in the Northern Ireland Criminal Justice System
• 6 Responsibilities and Obligations of the Expert Witness
• 7 Emerging Science in Court
• 8 Statistics and the Expert Witness
• 9 The Expert Witness in the Inquisitorial Justice System Compared with the Adversarial Systems of the UK
• 10 Forensic Science in U.S. Criminal Trials after Melendez-Diaz
• Index