scientific expert evidence in the uk: proposing an abridged daubert
TRANSCRIPT
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Scientific expert evidence in the UK: Proposing an Abridged Daubert
Professor Jane L. Ireland*,
School of Psychology, University of Central Lancashire, Preston, UK; and Ashworth Research Centre
(ARC), High Secure Forensic Psychiatry, Mersey Care NHS Trust.
Professor John Beaumont
Lancashire Law School, University of Central Lancashire, Preston, UK.
*Authors note
Correspondence should be addressed to Jane L. Ireland, University of Central Lancashire, Preston, PR1
2HE, Lancashire, UK; E-mail: [email protected]
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ABSTRACT
Expert evidence is a contentious area with some high profile cases highlighting unreliable ‘scientific’
expert evidence. This commentary argues for improvement in the assessment of expert evidence
reliability. The history of developing legal criteria for admitting ‘scientific’ evidence will be considered.
An alternative to current approaches is proposed, including a Daubert application for generally accepted
physical sciences and Abridged-Daubert for novel and social/behavioural sciences. Also proposed is
increased involvement by experts in critically reviewing their own evidence and in providing statements
of limitations. The commentary concludes by outlining the importance of developing such an approach
for the UK legal system.
Key Words: Expert evidence; Admissibility; Scientific Evidence; Daubert
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Imagine being convicted on the basis of ear-print evidence for an offence you have not committed, even
when such evidence is known to be unreliable and not accepted by the wider scientific community.
Alternatively, consider being placed in prison for murder on the sole basis of a dog detecting your scent
after an article of your clothing has been placed in a coffee can. Or what of being accused and placed on
remand for allegedly bringing a giraffe and elephant into a Sunday school as part of suspected ritual
abuse of children; later killing these animals and hanging the children upside down from chandeliers on
the (incorrect) basis that children as young as three or four have intact memories and are not
suggestible? These may sound like plot lines from movie scripts, but they are not, having already been
played out in courts, leading to convictions later questioned or overturned (i.e. Dallagher1; Winfrey2;
Akiki3 respectively). In all cases, experts proffered their evidence to be reliable, rigorous, scientific, and
of the highest quality.
Such evidence from experts is commonly considered under the broad definition of ‘opinion evidence’4.
This fails to allot such evidence the focused attention it requires, particularly considering the increased
significance of expert scientific evidence in courts5. Expert evidence is known to appreciably influence
decision-making, particularly if considered ‘scientific’6. Science though is a fluid concept, where new
techniques and approaches are constantly evolving7 and where it can be perceived to hold definitive and
reliable answers when this is not the case8. It is further assumed that it can be easily communicated9 to
1 [2002] EWCA Crim 1903 2 [2010] Tex Crim Ap No PD-0987-09 3 San Diego County Grand Jury Report of 1993-1994: Families in Crisis. Dale Akiki case. 4 C Tapper, Cross and Tapper on Evidence (12th Edition, OUP, Oxford, 2010), ch 11. 5 P Roberts, A Zuckerman, The Principles of Criminal Evidence (2nd ed, OUP, Oxford, 2010) 467. 6 D Omerod, A Roberts, ‘Expert evidence: Where now? Where next?’ Archbold (2006), June, 5 - 9 7 (n 5) 8 ( n 6) 9 (n 6)
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lay audiences, when in reality the evaluation of scientific evidence is complex10 and challenging to
test11.
Methods for testing the reliability of expert opinion evidence are crucial, with particular focus on what is
termed ‘evidential reliability’ or rather ‘trustworthiness’12 . Evidential reliability concerning the
scientific opinion evidence offered by expert witnesses will form the focus of this commentary as
opposed to other areas of concern such as expert qualification and evidence relevance13.
By exploring expert opinion evidence and its evidential reliability14, the commentary will set the scene
by first reviewing difficulties with unreliable expert evidence before progressing onto a critical review
of how courts have attempted to determine the quality of such evidence. This review will focus on two
sets of criteria that have featured prominently in the US court system, Frye15 and Daubert16, 17. The
benefits and challenges of attempting to develop criteria for admitting expert evidence will then be
considered, followed by suggestions for what could be included in a UK legal test of reliability. The
importance of maintaining a pragmatic approach18,19 will nonetheless remain at the centre of any
suggested procedure.
10 The Law Commission Consultation Paper No 190. The admissibility of expert evidence in criminal proceedings in England and Wales: A new approach to the determination of evidentiary reliability: A consultation paper. 2009; and Law Commission Paper No 325. Expert Evidence in Criminal Proceedings in England and Wales. 2011. 11 M Redmayne, Expert Evidence and Criminal Justice (Oxford University Press, Oxford, 2001). 12 (n 10) and reference to evidential reliability as ‘trustworthiness’ as opposed to consistency. 13 Keane, A. The Modern Law of Evidence (8th ed, Oxford University Press, Oxford, 2010). It is recognised that there are a broader range of issues in the arena of expert work (see n 5) but the focus of the current paper is reliability and admissibility of proffered ‘scientific’ evidence. 14 As opposed to validity or issues concerning consistency. 15 Frye v. United States [1993] 293 F 1013 16 Daubert v Merrell Dow Pharmaceuticals [1993] 509 US 579 17 Both of which are being considered for application to the UK system. 18 I Dennis, The Law of Evidence (4th Edition, London, Sweet & Maxwell, 2010) 850 19 (n 5)
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This commentary will therefore concern itself with three questions:
• Is there cause for concern about evidence reliability which suggests criteria are necessary?
• Are criteria already in existence that is relevant and has support?
• What can be proposed to determine evidence reliability, if required?
ANALYSIS OF EVIDENTIAL RELIABILITY OF EXPERT OPINION EVIDENCE
Problems arising from admitting unreliable expert evidence
Evidence from experts is admitted on the grounds that it meets the ‘helpfulness’ test20, 21 and assists
decision makers on issues outside ordinary experience (i.e. Turner Rule22). Once deemed helpful, focus
then shifts to evidence reliability. Complications can arise here for expert evidence23 presented as
scientific which is accepted with little or no question as to its reliability. A plethora of cases exist where
such evidence has significantly influenced final judgements but has later been considered unreliable or
requiring special consideration24. Example cases from the last decade25 include Clark (Sally)26,
Cannings27, Dallagher28, Winfrey29, Luttrell30, Jenkins (Siôn)31,George (Barry)32, and most recently
Knox and Sollecito33.
20 (n 18) and thus bringing value to the case and assisting the jury with details outside ordinary experience. 21 (n 5) 22 [1975] QB 834 841 23 The focus in this commentary is opinion evidence and thus use of the term ‘expert evidence’ is specifically referring to opinion evidence and not factual evidence such as that offered by other witnesses. 24 (n 10) 25 Not just including the UK but some pertinent recent cases. 26 [2003] EWCA Crim 1020 27 [2004] 2 Cr App R 7 28 (n 1)
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In Clark (Sally)34 appeal evidence focused on the admission of statistical data on cot deaths. The Court
of Appeal considered the data flawed and the expert to have misrepresented statistics. This led to the
overturning of a murder conviction for the defendant. Similarities were also drawn with Cannings, with
this involving three infant deaths and the same expert misrepresenting statistics. The defendant in this
case also had their conviction overturned.
Dallagher35contrasted to these cases in its use of untested methods being admitted as reliable. As noted
earlier, this case involved the use of ear prints, but it failed to account for this representing a novel
scientific advance without general scientific acceptance36. The defendant was convicted but released on
appeal when it was demonstrated that the ear print belonged to someone else. The evidence was further
criticised on the grounds that a decision for conviction included over-focus on a single element of
scientific evidence, an issue which will be returned to later37.
Whereas Dallagher focused on the use of a novel method and the problems associated with this, Winfrey
was applying a method considered routine38 but where scientific testing and application was poor.
29 (n 2) 30 R v Gerrard Francis Luttrell and others [2004] EWCA Crim 1344 31 R v Jenkins (Siôn) [2004] EWCA Crim 2047 32 R v George (Barry) [2007] EWCA Crim 2722 33 A recently overturned case (3rd October 2011) involving the death of Meredith Kercher, which led to the conviction of Amanda Knox and Raffaele Sollecito in Italy in 2009. See N Squires, ‘Amanda Knox freed: tears of joy as four-year nightmare is over – Telegraph’ (The Daily Telegraph, London, 3rd October 2011). 34 (n 26) 35 (n 1) 36 C Champod, B Kuchler, I Evett, ‘Earmarks as evidence: A critical review’ Journal of Forensic Sciences (2002) 46/6, 1275-1284. 37 (n 31, 32, 33) 38 (n 10) where it is discussed how knowledge may become generally accepted even without robust examination of its methodology. It lacks, however, the methods required to deem it scientific.
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Winfrey applied osmological evidence (Wojcikiewicz, 199939), specifically dog scent analysis40, to
secure a murder conviction. The defendant was sentenced after bloodhounds located his scent on the
victim’s clothing and matched it to a sample of the defendants scent placed in a coffee can. The expert
evidence was considered compelling by the jury and represented the primary evidence in the original
trial, but was overturned on appeal due to poor reliability41.
A willingness to admit expert evidence despite queries over its reliability, contrasts to Gilfoyle42 where a
‘psychological autopsy’ was conducted on the deceased. The courts rejected this evidence on the basis
that its reliability was unknown; there was no means by which the opinions could be tested, an absence
of academic support for the methods, and no database that could be drawn upon. In addition the expert
had never conducted such an assessment previously. Gilfoyle is distinguished from the other cases
presented, since expert opinion was not permitted admissible. This indicates existence of a threshold in
some cases, where evidence can be rejected on the basis it is not sufficiently reliable. Despite existence
of a threshold there appears inconsistency with which it is applied.
This is captured well in the case of Luttrell43. Here, expert evidence focused on admissibility of lip-
reading evidence using videos. Defendants were convicted of conspiracy on the basis of such evidence.
On appeal it was held lip reading met the criteria for evidence reliability and was thus admissible.
However, it was deemed such evidence could be admitted only if it carried a warning as to its limitations
39 J Wojcikiewicz, ‘Dog scent line-up as scientific evidence’ (1999) accessed via http://www.forensic-science.com on 04.07.2011. 40 See State v Cross [2009] 681 S E 2d 566 WL 2177766 as a further example of courts considering such evidence. 41 (n 39) 42 [2001] 2 Cr App R 5. Where ‘psychological autopsy’ refers to completing a psychological assessment on a deceased individual. 43 (n 30)
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and likely error rates44. In this instance courts appeared to be submitting potentially unreliable evidence
with caution. This contrasts to the earlier cited cases of Clark (Sally), Cannings, Dallagher and Winfrey.
Finally, are cases such as Jenkins (Siôn)45, George (Barry)46, Knox and Sollecito47where limited forensic
evidence was focused on without commentary on its reliability. In Jenkins (Siôn), the defendant was
convicted of the murder of his foster daughter due to 158 microscopic bloodspots on his clothing. The
forensic evidence was later deemed unsafe. An alternative explanation was indicated, namely the
bloodspots were the product of a blood clot and release of air as the victim, Billie-Jo, died whilst he was
tending to her injuries. Following two subsequent retrials, juries failed to reach a verdict and Jenkins
was released.
A more extreme example of narrow unreliable evidence, convincingly argued by expert witnesses,
occurred in George (Barry)48 where a single microscopic particle of what was supposed to be gunshot
residue, and a single fibre on his clothing, linked him to the murder of a TV presenter, Jill Dando. He
was acquitted after seven years, when it was successfully argued that this residue could have been
transferred from armed officers attending the scene and via a mannequin that the defendants clothing
was placed on to take the forensic photographs.
The key issue in the George (Barry) case was the jury failing to be advised by the expert witnesses of
the risk for contamination of evidence, and thus failing to critically review the evidence they offered.
44Also referred to as ‘margins of error’ or ‘confidence intervals’. These represent an indication of how confident you can be that the evidence is accurate and where the ‘true’ data is likely to fall within a range. 45 (n 31) 46 (n 32) 47 (n 33) 48 (n 32)
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Similar issues were raised in the recent case of Knox and Sollecito49 following the murder of a student in
Italy. The evidence used to convict the defendants focused on DNA tests which linked them to a knife
(later noted to be incompatible with the murder weapon), the bra clasp of the victim (which was left at
the scene for six weeks, untouched) and bloodstained footprints. The appeal case focused again on the
reliability of the expert testimony presented at the original trial, and the failure of experts to recognise
and report the contamination caused to the forensic evidence. What Knox and Sollecito indicates, is the
continuing significant difficulties in the application of expert ‘scientific’ evidence, despite a wealth of
preceding high profile cases, and apparent failure to learn from previous miscarriages of justice50.
This brief review illustrates how problems can arise when expert evidence is admitted without
consideration of its reliability, particularly if it has become the focus of a case and there has been a
failure to disclose errors. The UK legal system has not, until recently, considered reliability in any
detail51. Complexity remains, with the question not simply one of determining the reliability of
evidence but also how reliability can be assessed and how limitations on reliability should be
communicated. This point is essential. As noted by Roberts and Zuckerman (2010), the benefits of
expert evidence should not be minimised as it undoubtedly has value. Rather, the issue is one of the
problems that can arise when the evidence is misrepresented or its reliability over-emphasised52.
This relates to a fundamental issue, particularly that involving new forms of evidence. Courts need to
distinguish between ‘accepted’ and ‘novel’ scientific evidence but to commit to critically reviewing both
49 (n 33) 50 (n 5) 51 (n 10) 52 (n 5)
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and not assuming the former automatically has reliability53. Indeed, automatically excluding novel
evidence prematurely, before testing, can raise challenges54. This was captured in Clarke (RL)55 and
Harris and others56 where the court directed that evidence could not be restricted or refused solely on
the basis that it represented a novel scientific advance. Thus, ascertaining a means of determining
reliability for ‘generally accepted’ or ‘novel’ scientific expert opinion becomes crucial. This is the focus
of the ensuing section.
What can be applied to determine evidential reliability?
The cases noted thus far support a case for testing expert opinion for reliability. Until recently the UK
court system has been relaxed on this issue and criticised for the absence of specific criteria57.
Consequently, UK judges are provided with no guidance on how they should determine evidential
reliability. However, the absence of detailed admissibility criteria beyond very basic ‘relevance and
reliability’58 has been commended as pragmatic and a means of ensuring no inhibition of potentially
valuable expert evidence being admitted59. Thus a simple system, such as that found in the UK, is not
necessarily a poor one. Indeed, Roberts and Zuckerman (2010) argue for a retained simplistic approach
to admissibility, advocating solely for the ‘helpfulness’ element of Turner60, namely, if the evidence
does not assist and risks distraction then it should not be admitted regardless of its scientific rigour.
53 (n 5) 54 (n 6) 55 [1995] 2 Cr App R 425 56 [2005] EWCA Crim 1980 57 (n 10) 58 JA Dvoskin, LS Guy, ‘On Being an Expert Witness: It’s not about you’ Psychiatry, Psychology and Law, 2008, 15(2), 202-212. 59 (n 10) 60 (n 5)
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Nonetheless, the series of cases noted earlier in which expert evidence was indicated to be unreliable,
suggests that more is required than a simple determination of ‘helpfulness’. There has been a focus
elsewhere on developing detailed admissibility criteria which has influenced practice in the UK and is
thus worthy of consideration. One influential case is the Australian case of Bonython61. Three factors
were considered relevant here to determining evidence admissibility; that the evidence was part of
specialised knowledge or experience; that opinion was derived from a reliable body of knowledge or
experience; and the witness had the required experience to express an expert opinion.
Then there is the US system, using the grounding case of Frye62, to deem testimony could only be
admitted if ‘generally accepted’ in the field. Unlike Bonython, this excluded admission of novel
evidence. Bonython has, however, been described as a simple restatement of Frye in part63, illustrating
the close cross-over between these tests. Frye though failed to propose a means of testing the evidence
once ‘general acceptance’ was reached. The previously described case of Winfrey64, for example, would
pass Frye on the ‘general acceptance’ principle concerning osmological [dog scent] evidence. However,
a lack of testing and failure to account for false positive rates65 would make this evidence unreliable,
thus illustrating the problems with Frye.
Due to mounting criticism66, Frye was superseded by a further US case, that of Daubert v Merrell Dow
Pharmaceuticals67 where the 1975 Federal Rules of Evidence68 took precedence. Here, admissibility of
61 [1984] 38 SASR 45, 46-47. This forms part of common law in England and Wales. 62 (n 15) which focused on the admissibility of polygraph evidence. 63 D Omerod ‘The Law Governing Reliability and Admissibility in Criminal Trials’ (2008) http://www.northeasterncircuit.co.uk/documents/Ormerod_CBA_lecture_experts_26_april.pdf accessed 10.07.2011. 64 (n 2) 65 Where an individual is falsely identified to have committed an act. 66 (n 10)
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scientific knowledge focused on appropriately qualified experts, relevance and reliability69. The latter
criteria included evidence based on a testable theory or technique; evidence subjected to peer review;
inclusion of a known error rate70; standards in place to control its use; and a basis in generally relevant
science, with the latter an element clearly relating to Frye. Generally referred to as the Daubert
Criteria, they are being considered for application to the UK criminal law system71. They have also
been applied with some success to support the admissibility of non-scientific testimony (e.g. Kumho Tire
v. Carmichael72).
Criticisms of using criteria to determine reliability
In 2000, Federal Rule 702 was amended to include additional provisions whereby expert evidence could
be admitted only if based on sufficient facts or data; if it was the product of reliable methods; and if
these methods had been applied correctly and reliably73. Thus there appeared a move to how reliable the
witness was as an information-giver as opposed to how reliable the expert opinion was that they offered.
These improvements did not satisfy critics, with some arguing that what started as a “well-intentioned
attempt to ensure reliable and relevant evidentiary science has had troubling consequences”74 (p 3). One
of the most significant of these has been the exclusion of evidence from juries that did not pass the
67 (n 16) 68 Federal Rules of Evidence, Rule 702 69 (n 11) 70 (n 44) 71 (n 10) 72 [1999] 526 US 137 73 (n 68) 74 Tellus Institute, ‘Daubert: The most influential supreme court ruling you’ve never heard of’ (A publication of the Project on Scientific Knowledge and Public Policy, Boston, US, June 2003).
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Daubert Criteria. This has served to limit prosecution evidence and strengthen defences75. It has also
excluded some legitimate novel or social/behavioural sciences from proceedings76. An example has
been the weight placed on peer review which serves to exclude novel scientific advances, even with
sound methodology77. Indeed, Daubert is liberal when the admitted evidence is well recognised and
researched but too strict when the science is novel or primarily social/behavioural. For the latter, Frye
offers a more relaxed application but has been duly criticised for its liberal nature78.
Despite criticisms of Daubert, it remains one of the most clearly outlined criteria for evidence
admissibility79. It has already had some application in the UK, namely in the case of Dallagher80 when
dealing with the concept of novel scientific evidence. Frye was not considered stringent enough for this
case, with the court opting for what they thought was a more lenient Daubert approach. This
misunderstanding of Daubert suggests that even in its limited application to the UK it has not been
accurately applied or understood81.
For example, in Dallagher, the court had actually applied the ‘general relevance’ element of Daubert
only, disregarding the Frye criteria of ‘general acceptance’. It is true that Frye is stricter on this single
issue but once you consider the additional criteria of Daubert it is apparent that Daubert has stricter
application. The interesting point from the application of Daubert in Dallagher is that even when
admissibility tests have been applied in the UK the focus has not been on reliability but relevance, e.g.
75 (n 74) 76 (n 74) 77 (n 10) 78 D Faigman, M Saks, J Sanders. ‘How good is good enough? Expert evidence under Daubert and Kumho’ Case Western Reserve Law Review (2000), 50, 645-647. See also (n 5). 79 (n 10) 80 (n 1) 81 (n 74)
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‘why should we care’82. This is a result of the UK system continuing to apply only a rudimentary
principle for admissibility (i.e. Turner Rule) and focusing therefore on including expert evidence outside
typical knowledge. Turner does not have a role, however, in testing evidential reliability, representing
little more than a statement of how evidence should be included and not how it should be tested.
Thus there are a range of issues that require consideration when determining evidential reliability. The
UK system has largely avoided these, focusing more on basic issues, such as admissibility relevance
(Turner Rule), how experts should be used and when83,84. It has avoided the complexity and debate that
has developed around using criteria to determine evidence reliability. Nonetheless, UK Courts do need
some means of sufficiently testing the assertions of their experts85 and distinguishing between science
and junk-science86. The UK cases indicated earlier (e.g. Clark (Sally), Cannings, Dallagher, George
(Barry) and Jenkins (Siôn)) where admitted expert opinion has been deemed later to be unreliable,
provide a basis for ensuring this issue is fully considered across all breadth of legal proceedings.
The UK system needs to embrace these issues in their development of a more rigorous approach to
assessing the reliability of expert evidence87 whilst seeking to avoid difficulties evidenced in the
experiences of other court systems. Although there may be temptation to adopt what appears well-used
criteria from other countries (e.g. Daubert), it will be important to account for challenges in these
82 (n 58) 83 Civil Procedure Rules Pt 35; Criminal Procedure Rules, Pt 33 84 (n 5) 85 (n 6) 86 (n 18) 87 (n 63)
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approaches88. The ensuing section will outline some proposals that could be considered by the UK legal
system.
WHAT CAN BE PROPOSED TO DETERMINE EVIDENTIAL RELIABILITY FOR EXPERT EVIDENCE
IN THE UK?
As illustrated in this commentary, action is required to improve the criteria for the admission of reliable
expert opinion evidence89, particularly in the UK where there is no detailed guidance on examining
reliability90. The importance of addressing this area is an accepted theme within the literature91, with
criterion approaches (such as Daubert) appearing to have value once correctly applied, particularly to
physical sciences92. Indeed, misapplication of these approaches is based on a poor understanding of
how they should be used93. Of the approaches presented the revised Daubert criteria94 has obtained the
most support, replacing Frye and applied more widely than Bonython. In broad terms, the Daubert
criteria to adopt would require the following components to be evidenced prior to the admission of
expert opinion, namely that it should be;
• Based on a testable theory or technique;
• Subject to peer review;
• Have a known error rate;
• Have standards in place to control its use; 88 (n 6, 63) 89 (n 5) 90 ( n 10) 91 (n 10) 92 Physical sciences include physics, biology, astronomy etc; referred to generally as ‘hard’ sciences. 93 (n 6) 94 (n 16, 68)
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• Have a basis in generally relevant science;
• Based on sufficient facts or data;
• The product of reliable methods;
• Used with a correct and reliably applied method by the expert.
It is argued here, however, that more is required than a simple application of these components,
particularly if the aim is to ensure evidence is not unhelpfully restricted95 or that social/behavioural or
novel scientific advances are not excluded96. For example, peer review, error rates, standards in place,
and sufficient facts and data, will not necessarily be evidenced by new or some social/behavioural
sciences. For novel and some social/behavioural sciences97, therefore, this would leave the following
useable criteria:
• Based on a testable theory or technique;
• The product of reliable methods;
• Used with a correctly and reliably applied method by the expert.
It could also be suggested that the main weakness of a criteria based approach to evidential reliability is
its failure to define what it meant by ‘science’. Regardless of what approach is adopted, either for novel,
social/behavioural or physical sciences98, it needs to be a pragmatic99 and not overwhelmed by detail.
95 (n 78, 56) 96 (n 56) 97 Including social sciences such as psychology, politics, criminology and sociology; or behavioural sciences, such as anthropology. These are referred to generally as ‘soft’ sciences. 98 (n 92) 99 (n 18, 5)
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Excessive detail will heighten the risk for individual interpretations, which has been one of the main
failings of Daubert100.
What the current commentary proposes instead is a two stage approach, a first stage where a series of
expectations should be met prior to the presentation of expert evidence, and a second where the evidence
is examined in court.
Stage one: Preparing for determining evidential reliability
It is proposed the core components of this stage include the following expectations:
• That the expert submits an information statement critically reviewing their opinions and
methods, further citing any recent advances in the field. This would allow experts to provide a
more balanced outline of their evidence to the Court and to distinguish between science with
considerable credentials, novel science, and common-sense evidence101. It should include
alternative explanations for opinions. Reference is made to the latter in Practice Directions102
but is rarely followed in practice where preference is for confident ‘absolute’ opinions103. The
information statement should also include content on what is needed to make the opinion
reliable, which in some instances may lead to a provisional opinion being indicated104. Experts
can also be invited to indicate, as noted later, exactly what category of science they believe they
are submitting under. 100 (n 1) as a good example of Daubert being misinterpreted. 101 (n 2, 6) 102 (n 83) 103 (n 6, 63) 104 (n 63)
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• That there is a clear definition of what type of evidence is being submitted. A rudimentary
definition of science has hampered the use of criterion approaches. This issue has been
completely missed by the various reviews into evidential reliability105. Even in the case of
Kumho Tire v. Carmichael this issue was not dealt with, where focus instead was on the
scientific method applied to physical (not social) evidence106. In order to determine how the
evidence can be tested for reliability there should be provisional agreement at this stage as to
which of the following categories the evidence primarily fits:
o Generally accepted physical sciences;
o Generally accepted social/behavioural sciences;
o Novel physical sciences;
o Novel social/behavioural sciences;
o Common-sense evidence.
What is not being suggested though is that stage one is equivalent to a Daubert Hearing107 where
advocates effectively test pre-hearing if the evidence can meet the criteria, rejecting its submission at
that stage if it does not. Such approaches have led, as noted earlier, to restrictions on the range of
evidence that a jury or decision-maker should be rightly exposed to108.
105 (n 4, 5, 6, 18, 10, 63). None of these sources make mention of this issue. 106 (n 72) where focus was on a damaged tire; the tire represents physical evidence and cannot be compared therefore to that indicated in some social/behavioural sciences. 107 (n 74) 108 (n 74)
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Adopting a Daubert-style hearing approach is inconsistent with the UK system of relevance (i.e. Turner
Rule) and would unfairly restrict the admission of novel scientific advances 109 and some
social/behavioural sciences110. Stage one is suggested here merely as a preparation stage to allow
advocates to collect the evidence they require to prepare for a detailed examination of the expert
opinion.
Stage two: Evidence examination
Stage two should lead to the exclusion of common-sense evidence on the basis of the Turner Rule.
Focus then moves to generally accepted science versus novel science. The five categories indicated
earlier (i.e. generally accepted physical sciences, generally accepted social/behavioural sciences, novel
physical sciences, novel social/behavioural sciences and common-sense evidence) would allow stage
two to apply criteria differentially. It is suggested here that the Daubert criteria is automatically applied
to generally accepted physical sciences, with an Abridged-Daubert proposed by the current paper to
apply to generally accepted social/behavioural sciences, novel physical science, and novel
social/behavioural science.
The only science that may cross Daubert and Abridged-Daubert would be generally accepted
social/behavioural sciences where occasions may arise where the science is closer in methodology to
physical sciences111. Adopting a pragmatic approach112, it is proposed this is submitted using Abridged-
Daubert with full Daubert used to supplement decisions. Abridged-Daubert is, admittedly, a lower 109 (n 56) 110 (n 97) 111 Some elements of cognitive psychology, neuropsychology or anthropology, for example, may include evidence that appears more in keeping with physical sciences. 112 (n 5, 18)
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level of reliability testing but would allow decision-makers to form their own view as to evidence
quality and avoid comparison to the more easily measurable physical sciences. Such an approach should
further reassure critics who argue for the removal of non-physical sciences from expert opinion
evidence113 because it cannot meet these prescribed criteria, even though this is inconsistent with the
importance of not restricting evidence114. Abridged-Daubert would at least allow for some evidence
testing.
Once evidence is deemed admissible on the basis of the criteria indicated here, the following principles
are then recommended;
• That all admitted evidence is accompanied by a statement of limitations, with this determined
largely on the basis of stage one. Precedents for this have already occurred in cases such as
Luttrell115. However, it is proposed this is not restricted to novel sciences but applied to all
evidence categories. This would allow all evidence to be tested equally without prejudice116.
The proposed statement of limitations should include a comment on the nature of the evidence,
namely if it is generally accepted science or a new advance.
• Disagreements between experts are acknowledged but not used to reject evidence.
Disagreements cannot be used as a basis to suggest that the science is flawed and all expert
113 See JT Richardson, GP Ginsburg, S Gatowski, S Dobbin, ‘The problems of applying Daubert to psychological syndrome evidence’ Judicature (1995) 79, 10; and M S Brodin, ‘Behavioural science evidence in the age of Daubert: Reflections of a skeptic’, Boston College Law School Faculty Papers (2004) 24, Berkley Electronic Press. Both outline problems in admitting non-physical science evidence. http://www.lacba.org/Files/Main%20Folder/Sections/Family%20law/Files/Shucart%202-2-05.pdf Accessed 29.06.2011. 114 (n 56) 115 (n 30) 116 (n 56)
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opinions therefore should be rejected as they lack reliability117. Disagreements between experts,
does not reduce evidential reliability but allows for a more thorough testing of opinion.
Reliability criteria were not designed to compare and contrast experts118. The stage one critical
review proposed here should nonetheless assist with communicating these difficulties.
Importance of a two stage approach
Adopting a two stage approach where the starting point is the clear definition of the type of scientific
evidence and subsequent provision of a critical review, would allow courts to indicate what type of
criteria (i.e. Daubert; Daubert-Abridged) should be applied. The inclusion of an automatic stage two
allows for all expert evidence to be submitted and reliably tested using shared criteria to determine
admissibility. Adopting different criteria dependent on the nature of the science has value and supports
the commentary in cases such as Harris119 where it was thought a single test could not apply to all
evidence. The proposed approach supports this and protects against the exclusion of scientific advances
and non-physical sciences, whilst also allowing for more rigorous testing of ‘generally accepted’
sciences, whether physical or social/behavioural.
CONCLUSION
This commentary aimed to identify issues surrounding evidential reliability and difficulties with the lack
of criteria in the UK. It posed three initial questions; 1.) Is there cause for concern about evidential 117 See R v Kai-Whitewind [2005] 2 Cr App R 31. A case involving the unexplained death of a child whom the mother had been accused of killing. The defence team noted disagreement between experts as a basis for their submission to argue for proceedings being unsafe. 118 (n 10) 119 (n 56)
22
reliability which suggests criteria are required? 2.) Are criteria already in existence that is relevant and
has support? 3.) What can be proposed to determine evidential reliability, if required?
The commentary aimed to answer the first two in the affirmative; there is cause for concern in the
absence of criteria120 and there appears a preferred criteria approach, namely Daubert. The problems
focus more on the overly strict application of such a criteria approach121. Such an approach also fails to
address the fundamental issue as to what type of science it is being applied to122. Problems have
occurred when its application has been beyond generally accepted physical sciences123, with the expert
evidence consequently being excluded124 on the basis that it does not meet criteria which it could never
actually meet. Thus although a criteria approach can assist in ensuring ‘junk’ science125 is excluded
from court, it may unfairly restrict evidence126, particularly that from social/behavioural and novel
sciences.
To answer the third question posed at the start of this commentary, it is argued that proposals can be
made to determine evidential reliability. The proposals focus on how criteria are applied as opposed to
their exact content. Proposed is a two stage approach whereby there is a classification and expert-
critique of the evidence (stage one), followed by an examination and limitation-giving component (stage
two). Common-sense or ‘junk’ science should be excluded by the process of stage one, allowing for
detailed and fairer consideration of a wider range of expert scientific opinion at stage two. In order to
120 (n 10) 121 (n 10) 122 (n 111) 123 (n 92) 124 (n 55, 74) 125 (n 18) 126 (n 55)
23
achieve this, it is argued that Daubert should apply for generally accepted physical sciences and an
Abridged-Daubert for social/behavioural sciences or novel scientific approaches.
What is suggested here is not an exact approach. For example, areas not addressed include the
importance of training advocates and decision-makers more thoroughly in the application of criteria
approaches and sciences more generally 127 , and training experts on what constitutes evidential
reliability128. What is clear is that the UK system requires some means of assessing evidential
reliability, with increased focus on the critical evaluation of all scientific expert evidence129. This
system should include evidence from a range of sciences and not exclude novel science130. It should
involve experts more in an assessment of their own evidence and qualification to use the methods they
apply in their evidence131, and place equal focus on the implementation of assessment criteria and
determination of its content. Underpinning the approach should be an acceptance that a range of science
can bring value to court, and that resolving all the problems associated with expert evidence is an
impossible goal to attain132.
127 (n 74) 128 (n 74, 18) 129 (n 5) 130 (n 56) 131 (n 6, 55, 74, 78) 132 (n 6)
24
BIBLIOGRAPHY
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26
Procedure
Civil Procedure Rules Pt 35
Criminal Procedure Rules, Pt 33
Cases
The Queen v Bonython [1984] 38 SASR 45, 46-47
R v Cannings [2004] 2 Cr App R 7
Kumho Tire v. Carmichael [1999] 526 US 137
R v Clarke (RL) [1995] 2 Cr App R 425
R v Clark (Sally) [2003] EWCA Crim 1020
State v. Cross [2009] 681 S E 2d 566 WL 2177766
R v Dallagher [2002] EWCA Crim 1903
R v George (Barry) [2007] EWCA Crim 2722
R v Jenkins (Siôn) [2004] EWCA Crim 2047
Daubert v Merrell Dow Pharmaceuticals [1993] 509 US 579
Frye v. United States [1993] 293 F 1013
R v Gerrard Francis Luttrell and others [2004] EWCA Crim 1344
R v Gilfoyle [2001] 2 Cr App R 5
R v Harris and others [2005] EWCA Crim 1980
R v Turner [1975] QB 834 841
R v Kai-Whitewind [2005] 2 Cr App R 31
Winfrey v The State of Texas [2010] Tex Crim Ap No PD-0987-09