In May 2022, The Expert Witness Institute is hosting a conference, with the title, The
Modern Expert: Relevant, Current, and Evolving.
I (Lisa Dickson) am going to lead a discussion on lessons to be learned about the
expert evidence in the adversarial trial process. I would like your views on to what
extent the experts were at fault in the cases of Clark and Cannings, and what we can
learn about experts in criminal trials form these 2 cases.
Background:
The cases of Clark and Canning clearly demonstrate the problems expert evidence
can pose to a trial. Both were charged with the murders of their children, after they
suddenly died. The experts were largely at fault in both cases – they gave evidence
outside their area of expertise, excluded evidence, used poor methodology, and
more. These issues resulted in Clark and Cannings’ release when the evidence
presented was shown to be unreliable.
Issues
Experts giving evidence beyond their area of expertise.
Expert paediatrician gave (inaccurate) statistical evidence on the chance of
two SIDS deaths in the Clark family. He was not a statistician and therefore
unqualified to make a valid and reliable claim about this. Lack of expertise can
cause an expert to use evidence in a way it was not intended to be used.
Statistics used in Clark were created to help identify families at a higher risk of
SIDS – not to diagnose an unnatural death at trial.
Impact experts and expert evidence can have on the jury.
It is easy for an expert with impressive credentials to influence a jury,
especially with information they do not easily understand. Expert evidence
can be confusing for an ordinary lay person - many people may believe that
the chances of a rare event occurring and a suspect’s innocence are the
same (Carriquiry, Dr Alicia.) Very problematic – how can a jury accurately
, assess the weight and reliability of expert evidence if they don’t truly
understand what the evidence being presented is?
Advocates dealing with evidence they do not understand.
Often, evidence presented by experts is also beyond the advocates’
knowledge. How can a lawyer adequately cross-examine the evidence give if
they do not understand it well enough? How can they properly scrutinize their
expert and ensure their reliability?
Possibility of expert bias.
Expert bias is a problem that is difficult to identify, control and fix. However, it
can have a huge impact on the evidence given and subsequent outcome of
the trial. In cases like Clark and Cannings, it has been argued that when an
expert is asked for their opinion on the cause of more than one case of SIDS
in a family, they will be prone to find the death unnatural. (Déirdre Dwyer,
2003.) Therefore, simply having expert evidence can cause bias.
Poor forensic investigation methodology.
In Clark - expert submitted swabs of the child’s throat, blood, body tissue and
spinal fluid for testing - which may have shown a different cause of death.
However - excluded this key evidence and the fact that tests were conducted.
Significantly affected the outcome of the trial - had there been guidelines that
these tests should be run on all suspicious infant deaths, the prosecution and
defense would have known of them and could have asked the expert
questions about them.
Laissez-faire approach to the admissibility of evidence.
No single test for admissibility of expert evidence. Often, evidence with
questionable reliability is simply left to the jury, who are instructed to decide
what weight to attach to it. As mentioned prior, it is easy for the jury to simply
defer to the expert - this can result in miscarriages of justice like Clark and
Cannings.
Domino effect of appeals when expert found unreliable.
Giving flawed evidence in the Clark trial undermined Dr Meadow’s reputation
and reliability as an expert. Led to Clark’s successful appeal and the reliability
of his evidence given in Cannings was questioned. As cases concerning SIDS
were not extremely common, the domino effect was not too significant.
However, had Meadows been an expert testifying in many murder cases, the
Modern Expert: Relevant, Current, and Evolving.
I (Lisa Dickson) am going to lead a discussion on lessons to be learned about the
expert evidence in the adversarial trial process. I would like your views on to what
extent the experts were at fault in the cases of Clark and Cannings, and what we can
learn about experts in criminal trials form these 2 cases.
Background:
The cases of Clark and Canning clearly demonstrate the problems expert evidence
can pose to a trial. Both were charged with the murders of their children, after they
suddenly died. The experts were largely at fault in both cases – they gave evidence
outside their area of expertise, excluded evidence, used poor methodology, and
more. These issues resulted in Clark and Cannings’ release when the evidence
presented was shown to be unreliable.
Issues
Experts giving evidence beyond their area of expertise.
Expert paediatrician gave (inaccurate) statistical evidence on the chance of
two SIDS deaths in the Clark family. He was not a statistician and therefore
unqualified to make a valid and reliable claim about this. Lack of expertise can
cause an expert to use evidence in a way it was not intended to be used.
Statistics used in Clark were created to help identify families at a higher risk of
SIDS – not to diagnose an unnatural death at trial.
Impact experts and expert evidence can have on the jury.
It is easy for an expert with impressive credentials to influence a jury,
especially with information they do not easily understand. Expert evidence
can be confusing for an ordinary lay person - many people may believe that
the chances of a rare event occurring and a suspect’s innocence are the
same (Carriquiry, Dr Alicia.) Very problematic – how can a jury accurately
, assess the weight and reliability of expert evidence if they don’t truly
understand what the evidence being presented is?
Advocates dealing with evidence they do not understand.
Often, evidence presented by experts is also beyond the advocates’
knowledge. How can a lawyer adequately cross-examine the evidence give if
they do not understand it well enough? How can they properly scrutinize their
expert and ensure their reliability?
Possibility of expert bias.
Expert bias is a problem that is difficult to identify, control and fix. However, it
can have a huge impact on the evidence given and subsequent outcome of
the trial. In cases like Clark and Cannings, it has been argued that when an
expert is asked for their opinion on the cause of more than one case of SIDS
in a family, they will be prone to find the death unnatural. (Déirdre Dwyer,
2003.) Therefore, simply having expert evidence can cause bias.
Poor forensic investigation methodology.
In Clark - expert submitted swabs of the child’s throat, blood, body tissue and
spinal fluid for testing - which may have shown a different cause of death.
However - excluded this key evidence and the fact that tests were conducted.
Significantly affected the outcome of the trial - had there been guidelines that
these tests should be run on all suspicious infant deaths, the prosecution and
defense would have known of them and could have asked the expert
questions about them.
Laissez-faire approach to the admissibility of evidence.
No single test for admissibility of expert evidence. Often, evidence with
questionable reliability is simply left to the jury, who are instructed to decide
what weight to attach to it. As mentioned prior, it is easy for the jury to simply
defer to the expert - this can result in miscarriages of justice like Clark and
Cannings.
Domino effect of appeals when expert found unreliable.
Giving flawed evidence in the Clark trial undermined Dr Meadow’s reputation
and reliability as an expert. Led to Clark’s successful appeal and the reliability
of his evidence given in Cannings was questioned. As cases concerning SIDS
were not extremely common, the domino effect was not too significant.
However, had Meadows been an expert testifying in many murder cases, the
