In July
I
reported about the so-called Breda 6 case in the Netherlands and how a
Bayesian argument was presented in the review of the case. My own
view was that the Bayesian argument was crying out for a Bayesian
network representation (I provided a model in my article to do that).
Now Richard Gill has told me the following:
Finally there has been a verdict in the 'Breda 6' case. The
suspects were (again) found guilty. The court is somewhat mixed with
respect to the Bayesian analysis: On the one hand they ruled that Frans
Alkmeye
had the required expertise, and that he was rightly appointed as a
'Bayesian expert'. On the other hand they ruled that a Bayesian
analysis is still too controversial to be used in court. Therefore
they disregarded 'the conclusion' of Frans's report. This is a remarkable
and unusual formulation in verdicts, the normal wording is that report has been disregarded.
This
unusual wording is no accident: If the court would say that they had
disregarded the report, they would lie, since actually quite a lot of
the Bayesian reasoning is included in their judgment. A number of
considerations from Frans's report are fully paraphrased, and sometimes
quoted almost verbatim.
Also I noticed that the assessment of certain findings is expressed in a nicely Bayesian manner.
However:
Contrary to Frans's assessment, the court still thinks that the
original confessions of three of the suspects contain strong evidence.
Unfortunately, the case is not yet closed, but has been taken to the
high court.
Frans Alkmeye
has also been appointed as a Bayesian expert in yet another criminal case.
The
ruling that the Bayesian analysis is too controversial is especially
disappointing since we have recently been in workshops with Dutch judges
who are very keen to use Bayesian reasoning - and even Bayesian
networks (in the Netherlands there are no juries so the judges really do
have to make the decisions themselves). These judges - along with Frans
Alkemade - will be among many of the world's top lawyers, legal
scholars, forensic scientists, and mathematicians participating in the
Isaac Newton Institute Cambridge Programme on Probability and Statistics in Forensic Science
that will take place July-Dec 2016. This is a programme that I have
organised along with David Lagnado, David Balding, Richard Gill and
Leila Schneps. It derives from our Bayes and the Law consortium which
states that, despite the obvious benefits of using Bayes:
The
use of Bayesian reasoning in investigative and evaluative forensic
science and the law is, however, the subject of much confusion. It is
deployed in the adduction of DNA evidence, but expert witnesses and
lawyers struggle to articulate the underlying assumptions and results of
Bayesian reasoning in a way that is understandable to lay people. The
extent to which Bayesian reasoning could benefit the justice system by
being deployed more widely, and how it is best presented, is unclear and
requires clarification.
One of the core objectives of the 6-month programme
is to address this issue thoroughly. Within the programme there are
three scheduled workshops:
- "The nature of questions arising in court that can be addressed via
probability and statistical methods", Tue 30th Aug 2016 - Tue 30th Aug
2016
- "Bayesian networks in evidence analysis", Mon 26th Sep 2016 - Thurs 29th Sep 2016
- "Statistical methods in DNA analysis and analysis of trace evidence", Mon 7th Nov 2016 - Mon 7th Nov 2016
