Lecture 4_ Experts _ the Justice System – Prt 1 .pdf

Law, Experts & Justice
Lecture 4:
Experts & the Justice System – Part 1

Law, Experts & Justice:
Experts & the Justice System
Agenda
• Forensic Science
• Types of Expert
• History of Court Experts
• Modern Use of Experts
• Judging Admissibility of Expert Evidence

Law, Experts & Justice: Introduction
• Science has been used in Courts of Law for centuries:
‘[I]f 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. For thereby it appears that we do not despise all other
sciences but our own, but we approve of them and encourage
them as things worthy of commendation.’
Buckley v Rice Thomas (1554)
• Courts would call on science when a dispute as to facts could
not be resolved due to lack of sufficient knowledge
• Post-Renaissance, the use of science in court grew with the
belief that science (rather than religion) was essential to
understanding the world

Introduction
• Science has proved to be useful, sometimes
invaluable in resolving legal disputes; but it is also
controversial and problematic
• Such problems have led to various proposals for
major change in the use of expert evidence (e.g. Law
Commission inquiries and proposals)
• Major change is ongoing:
➢ the closure of the Forensic Science Service in 2012
➢ ‘Science guides’ for judges issued in late 2017

Introduction
THREE BROAD AREAS OF CONTROVERSY
1. With forensic science as a discipline;
2. With the use of science in court generally;
3. With the use of any expert in court

The Purpose(s) of the Legal System
• Truth; honesty; justice; reliability; integrity; fairness;
regulation; control?
• The function and purpose of law is subject to a great deal of
theoretical debate.
• For our purposes it is important to understand that this
debate exists, and that the aims of the civil and criminal
justice systems may not be understood by lay people, lawyers
and scientists in the same way
• How we perceive the purpose influences our understanding of
the place of science in law (e.g. as a means to find ‘the
truth’)

The Purpose(s) of the Legal System
• Adversarialism: battle between two sides, with a winner who’s version
of the truth is accepted
• A ‘binary’ system: there must be a winning and a losing side in both
civil and criminal litigation
• Mistakes and uncertainty will inevitably result; but since we need a
‘winner’, uncertainty should be minimised
• Legally, the winner is officially established as ‘telling the truth’
regardless of whether that is objectively the case
• Mistakes can only be corrected via appeal – and the objective truth (or
at least something closer to it) may be discovered years later
• The role of science in this system is difficult as there may inherently be
uncertainties or multiple interpretations of factual information
• Science can assist adversarial truth-finding; or can be abused in order
to ‘win’

Forensic Science
• Forensic science is science that is used for the purposes
of the law or that appertains to the courts
• Derived from Latin for forum - “the practice and skill of making
an argument before a professional, political, or legal gathering”
(Weizman, 2011)
➢ Similar to advocacy; but ‘forensics’ could involve objects addressing the
‘forum’ (the gathering)
➢ Since objects cannot speak for themselves, there was a need for
interpretation/translation by a person
➢ This required a person to “mediate between the object and the forum:
to present the object, interpret it and place it within a larger narrative”
➢ As such, forensic experts ‘talk’ for things cannot – e.g. DNA, hair fibres,
blood, footwear, drugs, weapons, etc.

Forensic Science
If forensic science exists to assist legal decisions
(to interpret information for it) we should also
consider its methodologies and aims:
• how robust are its methodologies?
• what part is it expected to play?
• how influential should it be?
• what should be done about mistakes?

Types of Expert
Forensic Scientists?
• A person specifically employed to apply scientific methods to a type of
evidence for use in the legal system
• Conducts tests and interprets results; prepares a witness statement and
passes it to the police, who decide what further action to take, if any
• May appear as an expert witness in court
• Forensic Scientists are therefore both scientists and forensic experts
• Scientists: experts in their field able to generate and interpret evidence
in relation to it outside of the legal context
• Forensic Expert:
➢ a credible, authoritative, reliable and independent person who is a leader in their
discipline
➢ gives evidence on their area of expertise in the legal process to help resolve legal
disputes

Types of Expert
• Forensic Scientists are always classified as ‘experts’ in the context of the
law; but not all experts are forensic scientists
• Expertise can be drawn from a range of backgrounds and disciplines
(scientific and non-scientific disciplines)
• The range and variety of potential ‘experts’ has grown considerably – with
a blurring at boundaries as to what should be considered an ‘expert’ for
legal decision-making
➢ For example: the use of polygraphs remains controversial and
unacceptable to courts for the purposes of expert evidence
• A typology of problems
➢ Rogue Science: science with a spurious, questionable or fraudulent basis
➢ Rogue Scientist: a scientist who may be biased or who may be acting
outside of their area of specialisation

History of Court Experts
• The history of experts in court is tied to the evolution of the
legal system (particularly criminal procedure)
• Before the 18th Century, experts were involved in court
proceedings through two methods:
➢ Special Juries - juries consisting of experts (not in law)
➢ Individual advisors or consultants called by the court
• Since special juries judged guilt, this led to ‘trial by expert’
(rather than by one’s peers)
• In modern trials, an expert is allowed to comment on the
‘ultimate issue’ (i.e. the central legal issue of guilt/liability)
• Can only comment on the meaning of the specific evidence
which relates to their field of expertise

• Pre-18th Century ‘expertise’ also included forms that
we would not recognise today:
➢ Bury St Edmunds witch trial (1664) – the evidence of Sir
Thomas Browne on Danish witch trials and child witches
➢ Little criteria for judging its validity beyond Browne’s renown as
a physician, philosopher, and author
➢ Potentially subject to the bias of the individual ‘expert’ (Browne
was an avowed believer in witches)
➢ No ability to challenge this with contrary evidence – it was up to
the court to call witnesses or empanel a jury

• From the early 1700s onwards, a significant
culture shift towards adversarial procedures
• Defence lawyers began appearing to
represent defendants
• Adversarial expert testimony slowly emerged
as a practice (although unclear when this
started)
➢ The use of experts by each side to prove their
case

• Folkes v Chadd (1782): Often cited as the effective ‘birth’ of modern
adversarial expert testimony
➢ Various witnesses called by opposing sides in a dispute over the decay
of a harbour
➢ An objection to one witness (Thomas Smeaton, an engineer) on the
basis that he was offering only an opinion
➢ Led to an appeal, in which Lord Mansfield stated:
‘The opinion of scientific men upon proven facts may be given by
men of science within their own science’
• In short, a scientific expert could offer an opinion on established facts
• Note, the court did not necessarily approve of the adversarial form of
expert evidence (it did not consider partisanship)

• 19th Century Expert evidence:
➢ The rise of partisan (biased) evidence. This seems to have
developed gradually
➢ The era – the Industrial Revolution – saw increasing numbers of
scientists involved in expert testimony
➢ ‘Battle of the experts’ in the courtroom created major issues
with the use of expert evidence
➢ ‘a continuous parade of leading men of science zealously
contradicting each other from the witness stand’ (Golan)
➢ For example: Severn King v Imperial Insurance (1820) – ‘whale
oil to boil sugar’

Problems with Experts
The early issues of partisanship and ‘bias’:
• Partisan pressure corrupted expertise
• Experts disagreed and contradict each other
• No established criteria for being an ‘expert’
• Opinion testimony hard to evaluate and inherently unreliable (an
individual, subjective view)
• Experts can be badly prepared and fail to communicate
adequately
• Lawyers could manipulate and humiliate well-intentioned experts
(e.g. methods of questioning)
• ‘Educating’ the jury v ‘Commanding’ the jury

Lawyers v Experts
Criticism of Experts by Lawyers
• Contradictory and incomprehensible evidence was given;
• Jurors were confused and/or defer automatically to experts; and
• Experts were often partisan
Criticism of Lawyers by Experts
• The adversarial system creates disagreements (adversarialism)
• It insulted professionals of high integrity, treating them as ‘tools’
• It thwarted well meaning attempts to help juries to reach
decisions

Explanations for Problems
Arguably, a problem related to the approach to thought and knowledge at
the time…
Modernism
• A school of philosophy with origins in the notion that science could
provide immutable truths, or a ‘right way’ to see things
➢ Focus on objectivity, scientific method and empiricism
• The conclusions draw via this approach known as ‘paradigms’
• In terms of scientific inquiry, this was the dominant view throughout the
Enlightenment and beyond; BUT
• 20th Century: Post-structuralism/modernism questioned notions of
paradigmatic thinking and scientific realism

However, role of the expert is to provide certainty in the courtroom; the
notion that science itself could be uncertain has caused an uneasy
situation between the legal and the scientific communities.
Expectations of Law and Science
• Both Law and Science can be perceived as seeking to provide certainty,
but both can be equally uncertain or provide different answers to the
same question
• Both are complex subjects that often cannot (and arguably should not)
provide the certainty that is often demanded of it
• The belief that science could provide certainty to the law grew out of
the dominance of modernist thinking
• Post-modernism changed this by questioning what we can and should
expect from science

Modernism
We have a fixed state of knowledge that tells us the answer to a question (paradigm)
We move to a new paradigm when new evidence shows us something different
Post-modernism
We do not have a fixed state of knowledge and assume there is more than one possible
answer to any given question
We do not seek to adopt a position where we have the ‘right’ answer.

Modern Use of Experts
• The use of forensic science as dedicated forensic experts has
dramatically increased over the last 25 years
• The discipline derives from techniques originally developed in police
detection/investigation of crime
• For example: the development of the concept of unique fingerprints
➢ Introduced as a method of identifying criminals in mid 19th Century
India
➢ Posited as technique appropriate for forensics by Henry Faulds
➢ Scientific study of the concept undertaken and developed by Francis
Galton
➢ Led to acceptance as a form of expert evidence in the courts

Modern Problems with Expert Evidence
• Despite technological and scientific advances and knowledge of the
problems, they appeared to get worse, not better
• The Law Commission has recently reviewed the situation with a view to
changing the rules in relation to criminal proceedings (2009-2011)
• Contributing to the problem is the confusion between ‘fact’ and ‘opinion’
in relation to expert evidence:
➢ Experts are the only type of witness allowed to give opinion evidence as
opposed to factual evidence
Question: what weight should be given to an opinion because it is
given by an expert?

Expert Opinion
The problem with ‘opinion’ evidence:
• It is just that – an ‘opinion’ rather than a ‘fact’; one potential
interpretation
• Experts can, and do, may mistakes or make incorrect assumptions
(more on this later but e.g. Dallagher)
• The problem may be worse depending on the type of expert; we
identified different categories of expert:
➢ Forensic scientists; and
➢ Other forensic experts
• Fact-finders (primarily juries) may simply interpret the ‘opinion’ as ‘fact’
because of the nature of the witness
• This places great importance on the procedures for deciding who gets
to be an expert witness and when

Experts at the Pre-trial Stage
• Forensic scientists and experts in legal proceedings work in a
different way from the wider scientific and expert community
• Because they work for a party to the proceedings they have a
narrow and different objective
• Inability to entirely ‘direct’ the scope and direction of
investigation – the party they work for does
• Defence forensic experts will often be considering ‘second hand’
material:
➢ That is, material not generated or produced by the expert
➢ This will likely be material used in a prosecution case, which is
given to the defence
➢ ‘Unused’ material might also be available for expert opinion

Experts at the Trial Stage
• Problems at this stage have more to do with the ‘paradigm’
problem that we identified earlier
➢ That is, there are ‘certain’ answer to questions and the need for
the law to have a winner and loser
• Also problems of perception between lay juror, lawyers, judge
and expert
➢ For example, that the special knowledge/experience of an expert
means they are providing ‘facts’
• We will consider these issues in detail later in later lectures

Judging Admissibility of Expert Evidence
• A key question – what criteria should be used in deciding
whether expert evidence should be allowed?
• Cases that developed criteria for expert evidence; ‘gatekeeping’
in relation to the quality of evidence
• Frye (1923, US case): the opinion of an expert based on a
scientific technique must be ‘sufficiently established to have
gained the general acceptance in the particular field in which it
belongs’
• In short: do other experts deem the evidence reliable?
But how does this solve the problem of paradigms and
partisanship?

• Daubert (1993, US case): a court will judge whether evidence can be
admitted based on:
➢ Whether the theory/technique can and has been tested
➢ Whether it has been subjected to peer review and publication
➢ The known or potential error rate of the technique
➢ the existence and maintenance of standards controlling the
technique’s operation
➢ the scientific technique’s degree of acceptance in the relevant
scientific community
• In short: does the judge think the evidence is reliable?
But how does this resolve the problem that was identified earlier
in relation to possible unrealistic expectations of science?

England and Wales
• The Law Commission heavily criticised the laissez-faire approach to
admitting expert evidence in 2011
• It recommended a variety of changes to the law – which the
Government declined to enact
• Lundy v R (2013) provided a set of criteria that ought to be considered
by judges when assessing expert evidence that essentially copied
Daubert
• Furthermore, the Criminal Procedure Rules and Criminal Practice
Directions contain a variety of requirements effecting:
➢ Admissibility
➢ Content
➢ Procedure

Acknowledgment
This slides adopted form Matt Hall and Tomas Smith work.

Lecture 4_ Experts _ the Justice System – Prt 1 .pdf

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