Expert Witness Evidence in Sexual Assault Trials: Questions, Answers and Law Reform in Australia and England
| Published date | 01 January 2013 |
| DOI | 10.1350/ijep.2013.17.1.419 |
| Author | Annie Cossins |
| Date | 01 January 2013 |
| Subject Matter | Article |
EXPERT WITNESS EVIDENCE IN SEXUAL ASSAULT TRIALS
Expert witness evidence
in sexual assault trials:
questions, answers and
law reform in Australia
and England
By Annie Cossins*
Associate Professor, Faculty of Law, University of New South Wales
Abstract A review of the psychological literature shows that
jury-eligible citizens rely on a range of misconceptions based on victim
and gender stereotypes when assessing the credibility of sexual assault
complainants and rendering verdicts. Since these misconceptions
are likely to account for the high attrition and low conviction rates
in sexual assault trials in both England and Australia, this article
investigates whether or not educative information ought to be
admitted in these trials via an expert witness or a judicial direction. It
also investigates the type of expert evidence that would be admissible in
an adversarial context and the legislative models for doing so, based on
Australian reforms. The article concludes by making four recommen-
dations for reform to the laws of evidence in Australia, England and
Wales.
Keywords Sexual assault; Expert evidence; Judicial directions; Jury
misconceptions; Opinion rule
ike many other developed countries, the crime of sexual assault
in Australia and England and Wales is characterised by low
reporting rates, high attrition rates and low conviction rates at
doi:10.1350/ijep.2013.17.1.419
74 (2013) 17 E&P 74–113 THE INTERNATIONAL JOURNAL OF EVIDENCE & PROOF
L
* Email: a.cossins@unsw.edu.au.
trial,1indicating that a sex offence is one of the most difficult crimes to inves-
tigate and prosecute. It is likely that the feedback effect of low conviction rates
at trial influences the type of cases that police and prosecutors will investigate
and prosecute, as well as the low guilty plea rate for those charged with a sex
offence compared to other offences.2
Many have argued that because sexual assault is the type of crime where forensic
evidence may be unavailable or unable to prove a lack of consent, the problem is
one of evidence3or false complaints.4If a case involves the word of a complainant
against the word of a defendant, with little or no corroborating evidence, insuffi-
ciency of evidence is said to be both the problem and the reason for low conviction
rates at trial and high acquittal rates before trial.
The contrary argument is that myth, prejudice and disbelief surround the
reporting, investigation and prosecution of sexual assault,5producing a ‘culture
of scepticism’.6While this may account for the reluctance of police to investigate
some cases, a culture of disbelief also permeates the criminal trial, including the
jury room. It cannot be assumed that the average juror ‘has a good understanding
of all the insights that decades of psychological research have yielded’7about the
effects of sexual assault on victims. This means that jurors, making decisions
THE INTERNATIONAL JOURNAL OF EVIDENCE & PROOF 75
EXPERT WITNESS EVIDENCE IN SEXUAL ASSAULT TRIALS
1 J. Wundersitz, Child Sexual Assault: Tracking from Police Incident Report to Finalisation in Court (Office of
Crime Statistics and Research, SA: Adelaide, 2003); L. Ellison, ‘Closing the Credibility Gap: The
Prosecutorial Use of Expert Witness Testimony in Sexual Assault Cases’ (2005) 9 E & P239; L. Kelly,
J. Lovett and L. Regan, A Gap or a Chasm? Attrition in Reported Rape Cases, Home Office Research Study
No. 293 (Home Office: London, 2005); J. Temkin and B. Krahe, Sexual Assault and the Justice Gap: A
Question of Attitude (Hart Publishing: Oxford, 2008) 20–1; J. Fitzgerald, ‘The Attrition of Sexual
Offences from the New South Wales Criminal Justice System’, Crime and Justice Bulletin No. 92 (NSW
Bureau of Crime Statistics and Research: Sydney, 2006); K. Daly and B. Bouhours, ‘Rape and
Attrition in the Legal Process: A Comparative Analysis of Five Countries’ in M. Tonry (ed.), Crime and
Justice: A Review of Research (University of Chicago Press: Chicago, IL, 2010) 565.
2 Fitzgerald, above n. 1.
3 NSW Criminal Justice and Sexual Offences Taskforce, Responding to Sexual Assault: The Way Forward
(Attorney-General’s Department of NSW: Sydney, 2005); NSW Legislative Council, Standing
Committee on Law and Justice, Report on Child Sexual Assault Prosecutions (Parliamentary Paper No.
208) (Report 22) (NSW Parliament: Sydney, 2002).
4 I. R. Coyle, D. Field, P. Wilson, C. Cuthbert and G. Miller, ‘Out of the Mouth of Babes: The Case for an
Increased Use of Expert Evidence in Rebuttal of Sexual Abuse Allegations by Child Witnesses’
(2009) 33 Criminal Law Journal 139.
5 A. Cossins, ‘Children, Sexual Abuse and Suggestibility: What Laypeople Think They Know and
What the Literature Tells Us’ (2008) 15 Psychiatry, Psychology and Law 153; Ellison, above n. 1; Kelly,
Lovett and Regan, above n. 1.
6 Kelly, Lovett and Regan, above n. 1 at 14, 83.
7 S. J. Ceci and R. D. Friedman, ‘The Suggestibility of Children: Scientific Research and Legal Implica-
tions’ (2000) 86 Cornell Law Review 33 at 101.
about guilt and innocence, will be required to make assessments of credibility
‘that go beyond the layperson’s commonsense knowledge’.8
Based on their experience with the low probability of obtaining convictions:
prosecutors develop [anecdotal] knowledge about what jurors are
likely to look for in a sexual assault complainant … and whether the
circumstances surrounding the incident (e.g. prior relationship,
alcohol consumption) are likely to reduce the plausibility of the
complainant’s story.9
It is perhaps no coincidence that prosecutors and investigators look for the same
features that jury-eligible citizens have been found to focus on during their delib-
erations in mock trials, such as injury to the victim, use of a weapon and actual or
threat of force, clear expression of non-consent, corroborative medical evidence
and high emotionality of the victim.10 For example:
studies examining conviction patterns in sexual assault cases in
England and Wales … have indicated that claims of non-consensual
intercourse that are not accompanied by evidence of physical force
and … resistance are significantly less likely to be accredited as rape.11
The focus of prosecutorial decisions has been partly empirically validated in a
study which found that criminal proceedings were more likely to be instigated if
there was less than a 10-year gap between the offence and report to the police, ‘if
the offence involved some aggravating factor’ and if the victim was older than 10
76 THE INTERNATIONAL JOURNAL OF EVIDENCE & PROOF
EXPERT WITNESS EVIDENCE IN SEXUAL ASSAULT TRIALS
8 J. A. Quas, W. C. Thompson and K. A. Clarke-Stewart, ‘Do Jurors “Know” What Isn’t So about Child
Witnesses?’ (2005) 29 Law and Human Behavior 425 at 425–6.
9 N. Taylor, ‘Juror Attitudes and Biases in Sexual Assault Cases’, Trends and Issues in Crime and Criminal
Justice No. 344 (Australian Institute of Criminology: Canberra, 2007) 1.
10 Thiscan be seen from a comparison of the findings from D. Lievore, Prosecutorial Decisions in Adult
Sexual Assault Cases: An Australian Study (Office of the Status of Women: Canberra, 2004) and L. Ellison
and V. E. Munro, ‘Reacting to Rape: Exploring Mock Jurors’ Assessments of Complainant
Credibility’ (2009) 49 British Journal of Criminology 202. See also studies that have measured judges’
and investigators’ responses to different emotional states exhibited in victims’ testimony:
G. Kaufman, G. C. B. Drevland, E. Wessel, G. Overskeid and S. Magnussen, ‘The Importance of Being
Earnest: Displayed Emotions and Witness Credibility’ (2003) 17 Applied Cognitive Psychology 21; G. C.
Bollingmo, E. O. Wessel, D. E. Eilertsen and S. Magnussen, ‘Credibility of the Emotional Witness: A
Study of Ratings by Police Investigators’ (2008) 14 Psychology, Crime and Law 29.
11 Ellison and Munro, above n. 10 at 206; citing J. Harris and S. Grace, A Question of Evidence? Investi-
gating and Prosecuting Rape in the 1990s, Home Office Research Study No. 196 (HMSO: London, 1999);
Kelly, Lovett and Regan, above n. 1; J. Brown, C. Hamilton and D. O’Neill, ‘Characteristics
Associated with Rape Attrition and the Role Played by Scepticism or Legal Rationality by Investi-
gators and Prosecutors’ (2007) 13 Psychology, Crime and Law 355.
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