Lecture 9 (LEJ) BB.pdf

Law, Experts & Justice
Lecture 9:
Experts – solution or problem?

Law, Experts & Justice:
Overview
• Problems associated with experts
• Law Commission critique & proposals
• Examples of problems
• Attempts at reform and the future

Problems with Experts
Lack of control
• Experts can lack control over the materials they are asked to work with
• For example, collection at the crime scene influences testing in the lab, which
influences interpretation at a later stage
• Samples/evidence not in a perfect state (degradation, improper collection)
• A full range of relevant samples/evidence may not have been collected – for
example, digital forensic evidence
➢ ‘the average mobile phone today is capable of holding the data equivalent of
about 5 million A4 pages’ (AGO Review of disclosure, 2018)
➢ If key evidence is missing, can experts perform their role properly?
• Police/prosecution may be ‘selective’ about what they choose to focus on (e.g.
unused material); this can ‘skew’ the sample/evidence before expert is involved
• Defence experts and secondary access

Law, Experts & Justice: Problems with Experts
Forensic science does not happen in a vacuum
• Instrumental: a specific, limited purposes in investigation/litigation
• It is therefore not like objective scientific investigation
• Experts (particularly forensic scientists) will undertake directed
investigation
➢ For example, digital forensic scientists may only examine some devices even if
there may be relevant evidence elsewhere
• Reliability is often dependent on/strengthened by ability to replicate
results; BUT cannot usually repeat tests/examinations
• Perfect methodology? Or just best that can be done?
➢ Are all alternative options ruled out or is only evidence which supports the police
case provided?
➢ This only works if principle of equality of arms applies for defence i.e. equal
access to evidence/samples

Experts don’t always agree
• Specialised disciplines can accommodate a range of thought – there is
not necessarily one way to interpret data (and therefore evidence)
• However, the legal system seeks a high standard of certainty
(particularly criminal law) – remember, the binary system for
verdicts
• Pressure exists on experts, as instruments within this system, to provide
absolute answers; compounded by perception that experts can do so
• How adequately are qualified or provisional opinions on evidence
communicated during the investigative/court process?
• Mixed interpretations can cause confusion and uncertainty – anathema
to law !

‘Science’ is not necessarily exact
• The provision of opinion evidence can cause problems if such
opinions are relied on as verifiable fact – a classic example,
medicine:
➢ For example, definition and diagnosis of infections, diseases,
syndromes, etc. can be inexact and speculative (particularly
where there are overlapping symptoms)
➢ This is relevant to experts in the legal process – e.g. in a PI
case, establishing the nature of the injury and the cause is
crucial

Expertise lacks definition and restriction
• There is a lack of formal criteria for defining who can and should be an
expert
• Not only does this have implications in terms of quality but also in terms
of independence
• Can experts always be considered to be truly independent – and
therefore fulfilling their duty to the court?
• Particularly problematic at the early investigative stages of cases:
➢ They strongly influence the future direction of a case and the body of evidence
➢ If experts are considered to be part of the investigative team (e.g. forensic
scientists working for/with the police) can they disassociate themselves from
this?

Professional deference - ‘they are an expert, so they must be right’ !
• When an expert gives evidence, juries/magistrates/judges must weigh this
evidence for themselves
➢ Is this realistic? See the warning of Lord Hodge (previous lecture)
➢ Is the person making the statement more important than the content of the statement?
• In general life and other disciplines, we defer to experts (e.g. doctors, surgeons,
scientists, teachers, lecturers, toxicologists, surveyors, bomb disposal experts,
car mechanics, IT specialists/experts, etc.)
• This is both a matter of trust (when you lack knowledge); but also a matter of
professional courtesy
• How easy is it to lose this instinctive habit and consider ‘the evidence’ not ‘the
person’?
• Although, see the comments of Michael Gove and the ‘anti-expert’ movement…

Expert opinion evidence and the issue of proof
• An opinion is just that – not a fact ! It is an interpretation with limitations and
qualifications…
• ‘Proving’ certain things related to expert evidence raises issues:
➢ For example, proving a causal link may be difficult…
An expert may be able to say fact A exists (e.g. a defendant drove their
car into a victim’s car); and that fact B exists (e.g. the claimant has a
broken arm) – but demonstrating a link between the two to the requisite
standard may be difficult
➢ Correlation and causation are not the same !
➢ Experts will consider matters of probability (i.e. the likelihood that A caused B) –
but will jurors/magistrates understand these limitations?
➢ Will complexity/confusion cause adjudicators to abdicate responsibility to judge?

The ‘receipt’ of expert of evidence by different individuals
• ‘Fractured Lens’ theory suggests that different individuals perceive
and interpret information in different ways
➢ Individual characteristics/knowledge/experience shape interpretation of new
knowledge/info through a personalised ‘fractured lens’
• Objective data/evidence can be distorted by this, leading to different
interpretations (depending on who is receiving the data/evidence)
• The idea that expert evidence can provide objective, independent
evidence is potentially undermined by this inevitability. We might ask:
➢ How much of ourselves do we import into our decisions/views when presented
with information?
➢ Would someone who has been the victim of a similar crime have a different view
to someone who has not?
➢ What effect does this have on how jurors understand and interpret evidence?
➢ Are experts, in interpreting data/information/evidence immune from this?

An example: ‘K is mentally ill’ (Dorothy Smith, 1978)
“K was a young woman who came to be described by her friends and others as
‘mentally ill’, and Smith’s discussion focussed on how that conclusion was
reached. The data for the paper were contained in an interview that made
reference to various features of K’s behaviour over time. For example, her
friend had stated that when out on a hot day, K always ‘had to’ swim 30
lengths in the pool, that K cried nearly every morning in the car over ‘little
things’, that K worked in the garden for hours when there was ‘no need’, that
there were occasions when she couldn’t put on a teapot cover correctly, and
that she was none too keen on male company!
Smith examined these various statements in terms of the structure of the text
within the interview – how it identified and highlighted specific behaviours as
anomalous, how it authorized different persons to offer sound judgements
about K’s state of health, and ultimately how it was structured to establish (to
any rational reader such as you or I) the ‘fact’ that K was mentally ill.”
• Influencing factors: the observer; the motivation purpose of observation;
currently accepted social norms/dominant discourse in the area; presentation

Law Commission Review
“Expert evidence in criminal proceedings in
England and Wales”
• Started in 2009; concluded and reported in 2011
• A response to:
➢ Belief that ‘expert opinion evidence was being admitted in
criminal proceedings too readily, with insufficient scrutiny’
➢ Several high profile miscarriages of justice concerning
discredited expert evidence (Dallagher, Clark, Cannings, Harris)

The theoretical starting position in relation to experts is:
• They exist to educate the court on complex/specialised evidence
• Lawyers are able to effectively challenge and question such evidence to
ensure it is credible/reliable
• Fact-finders (e.g. juries) are adequately equipped to weigh this
evidence and render a fair and balanced verdict (in light of all evidence)
However, the Law Commission expressed serious concerns that:
• Experts did not always have the qualities and independence required
due to the laissez faire approach to admitting such evidence
• Lawyers were not confident enough or adequately equipped to
effectively challenge such evidence
• Juries tended to defer to experts, particularly in complex fields requiring
specialised ‘pre-knowledge’ (enhancing their persuasiveness)

Jury Deference - Good or bad?
• If the purpose is to use expertise when the court lacks it, surely it is logical
to defer to it? Only true if expert evidence is reliable
• The validity of this assumption therefore hinges on reliability…
➢ Unreliable evidence means a ‘risk that juries may simply defer to ostensibly
reputable experts and accept their opinion evidence at face value’ (Law
Commission)
➢ Juries/mags may have insufficient understanding of the limitations of expert
evidence to question it themselves
➢ Lawyers may fail to effectively challenge it, and thus fail to provide juries/mags with
a more complete understanding of the value of the evidence
➢ A loose test of admission may present dubious expertise to the court, which is
accepted and is hard to challenge on appeal
• Raises questions about the quality of decision-making by juries/mags
based on such evidence (juries do not explain their verdicts)

A Flawed Framework
Lord Justice Leveson, 2010:
‘It is, in my opinion, perfectly clear that expert evidence
of doubtful reliability may be admitted too freely with
insufficient explanation of the basis for reaching specific
conclusions, be challenged too weakly by the opposing
advocate and be accepted too readily by the judge or
jury at the end of the trial. In that regard, therefore, the
law of England and Wales is not satisfactory and reform
is undoubtedly required.’

Experts and Miscarriages of Justice
R v Dallagher (Mark) [2002] EWCA Crim 1903
“D’s conviction for murder was based on unreliable expert opinion
evidence relating to the comparison of an ear-print made by D with
a latent ear-print found on a window. At D’s trial, one of the
experts opined that he was “absolutely convinced” that D had left
the latent print, and a second prosecution expert was willing to
countenance only a “remote possibility” that the latent print had
been left by someone else. Notwithstanding the strength of these
opinions, DNA evidence taken from the latent print subsequently
established that it had not been left by D, demonstrating the
unreliable nature of the evidence used to secure his conviction”
(summary from the Law Commission review)

R v Clark (Sally) [2003] EWCA Crim 1020
‘[A]n expert paediatrician gave unreliable opinion evidence. This expert,
who was not a statistician, had formulated his opinion on the assumption
that there were no genetic or environmental factors affecting the likelihood
of naturally occurring cot deaths, opining that there was only a one in 73
million chance of two such deaths in the same family. The Court of Appeal
took the view that the figure grossly misrepresented the chance of two
sudden deaths within a family from unexplained but natural causes, and
added that if the issue of the statistical evidence had been fully argued it
would probably have provided a distinct basis upon which to allow C’s
appeal. The court also noted that the way the expert had presented his
evidence could have had a major impact on the jury’s deliberations.”

R v Clark (Sally) [2003] EWCA Crim 1020
• In addition, a prosecution expert failed to disclose
test results for one of Clark’s deceased children
• This failure had ‘fallen a very long way short of
standards to be expected of someone in his position
upon whose evidence the court was inevitably going
to be dependent’
• It was on this ground of appeal, primarily, that Clark’s
conviction was quashed

R v Cannings (Angela) [2004] EWCA Crim 1
“C’s convictions for the murder of her two infant sons had been based on
the dogmatic expert view (that is, a view based on a hypothesis which had
not been sufficiently scrutinised or supported by empirical research) that
the mere fact of two or more unexplained infant deaths in the same family
meant that murder had been committed. The Court of Appeal quashed C’s
convictions. Fresh evidence suggested that multiple cot deaths in the same
family could have an underlying genetic cause; and a report relating to the
largest follow-up study of cot-death families concluded that “the
occurrence of a second unexpected infant death within a family is …
usually from natural causes” ”

R v Harris and others [2005] EWCA Crim 1980
In Harris and previous cases, “the prosecution had been allowed to rely on
a hypothesis that a non-accidental head injury to a young child could
confidently be inferred from nothing more than the presence of a
particular triad of intra-cranial injuries. The prosecution had in effect been
able to rely on nothing more than expert opinion evidence based on the
triad to secure convictions for very serious offences against the person,
including murder. This was the case even though the diagnosis of a violent
assault was predicated on empirical research which has been criticised as
comprising only a small, poor quality database. In other words, the
hypothesis underpinning the diagnosis had been insufficiently scrutinised
or supported by empirical research to justify the strong opinion evidence
founded on it.”

R v Harris and others [2005] EWCA Crim 1980
• In short, there was a generally accepted medical view
(a dominant discourse) in relation to this type of head
injury
• This led to an effective ‘presumption of guilt’ by the
medical profession, and in turn, the fact-finders
• Reliance on this evidence alone (coupled with the
problem of deference) suggests trial by experts, not
juries

• MOJ: a major catalyst for reform in this area (and many others)
• The cases we know about may only be a very small number
• Redmayne (2001) identified cases in which unreliable forms of expert
evidence were admitted and resulted in the evidence being discredited
• Whilst not exhaustive, the following list indicates fields of concern:
➢ Voice identification based solely on auditory comparison
➢ Stylometry (attributing authorships through style)
➢ Handwriting comparisons
➢ Diagnoses of ‘battered women syndrome’
➢ Theory of repression and recovery which underpins the admissibility of
recovered memories of sexual abuse
• Redmayne considered his list to be the ‘tip of the iceberg’ (with the Law
Commission agreeing in its consultation document)

‘Little is … known about the true error rates for almost all forensic
science techniques. The few disclosed error rates, however, are
shockingly high. Most of forensic science operates outside of the
peer review systems, and forensic science is seldom published.
While forensic science techniques are accepted in forensic science,
many are not accepted by a broader scientific community.
Furthermore, the techniques accepted in forensic science are not
used in such a way that would reveal their methodological flaws, if
any.’ (Jonakait (1995), quoted in LC consultation, 2009)
• A lack of empirical testing, peer-review and validation
therefore feeds unreliable evidence into a system not
equipped to challenge and judge its value

Fundamental concern of the Law Commission was therefore:
• Expert evidence may not be reliable or properly tested
• The innocent may be convicted; and the guilty are freed
• This not only undermines the purpose of the criminal justice system; it
leads to a lack of public confidence
There have been suggestions for reform before the review:
• Redmayne (2001) suggested ‘the court … screen[ing] expert testimony
to ensure that jurors will not be put in the position of deferring to
unsound opinions’
• HoC Science and Tech Committee, ‘Forensic Science on Trial’ (2005)
➢ Various key stakeholders should develop a new test for determining
admissibility

Law Commission proposed four options in its consultation:
1. Exclusionary discretion without guidance
– expert evidence should be treated like any other evidence (e.g. refusal if its
probative value is outweighed by risks of misleading, confusing, etc.)
2. Exclusionary discretion with guidance
– as above, but specific guidance would be provided to the judge in order to
determine reliability of evidence
3. An admissibility rule requiring consensus amongst experts in the field
(i.e. a Frye type test)
4. An admissibility rule requiring the trial judge to assess the evidentiary
reliability of the tendered evidence (i.e. a Daubert type test)
– a test to determine the validity of the methodology/hypotheses underpinning such
evidence

Law Commission Proposal
Law Commission’s final proposal:
‘[A] new reliability-based admissibility test
for expert opinion evidence which would need
to be applied in relation to most expert
opinion evidence tendered for admission in
criminal proceedings’

The ‘reliability’ rule should look as follows:
• The opinion evidence of an expert witness is admissible only if the
court is satisfied that it is sufficiently reliable to be admitted.
• The opinion evidence of an expert witness is sufficiently reliable to be
admitted if:
a) the evidence is predicated on sound principles, techniques and assumptions
b) those principles, techniques and assumptions have been properly applied to the
facts of the case; and
c) the evidence is supported by [that is, logically in keeping with] those principles,
techniques and assumptions as applied to the facts of the case.
• The judge should have a single set of guidelines to assist and should
be able to call on an independent expert (exceptional)

It also set out key examples of when evidence might not be
reliable:
• the opinion is based on a hypothesis which has not been subjected to
sufficient scrutiny or which has failed to stand up to scrutiny
• the opinion is based on an unjustifiable assumption
• the opinion is based on flawed data
• the opinion relies on an examination, technique, method or process
which was not properly carried out or applied, or was not appropriate
for use in the particular case
• the opinion relies on an inference or conclusion which has not been
properly reached
It also provides a list of generic factors a judge should consider

In addition:
• Recommended codification of rules on admissibility with three
basic requirements:
(a) the court is satisfied that the evidence would provide
information which is likely to be outside a judge or jury’s
experience and knowledge, and which would give them help
they need in arriving at their conclusions
(b) the person who gives the evidence is qualified to do so, and
(c) the evidence is not made inadmissible as a result of impartiality
of the expert

Law, Experts & Justice: Law Commission Review
• These suggestions have not been acted on by the Government
• Viability of the Law Commission’s solution?
➢ ‘there needs to be a change in culture and levels of technical
sophistication among practising lawyers and judge’ (and to be able and
willing to do so) (Edmond, 2012)
➢ significant questions about underlying rigour and unbiased nature of
various forensic sciences which can’t be addressed by these solutions
(legal v scientific acceptance)
➢ does not solve the problem of jury deference – and may even in
entrench it (since juries may assume they can absolutely trust experts
whose evidence is deemed ‘reliable’ by the court)
➢ The reliability test can be disapplied in some cases – ‘some indication
of reliability should be required of all types of expert opinion evidence’
(Edmond, 2012)
➢ Some weak expert evidence may still be admissible in the context of
certain types of cases

Conclusions
• The LC proposals – in the right direction, but not ‘a panacea’
(Law Commission)
• A systems problem? Is the system that requires change rather
than standards applied to experts in this system?
• Not taken up and therefore only persuasive on current
approaches rather than absolutely binding via statute
You should now be able to:
• critically engage with the issues raised by the use of expert
evidence in criminal and civil cases, and
• the likely issues that may arise from the proposed reforms

Acknowledgment
This slides adopted from Matt Hall work.

Lecture 9 (LEJ) BB.pdf

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