Lecture at UC to ask what if judges could understand forensic experts?
March 24, 2013
In courtrooms judges have to make decisions based on the available evidence. This evidence is nowadays often very
technical and statistical and difficult to understand, which can frustrate judges.
Forensic experts who write their reports try to be as exact as possible and they on their part are frustrated when the
judges seem to misunderstand them.
A visiting expert from the University of Amsterdam, Professor Joep Sonnemans, will give the 2013 New Zealand
Experimental Economics Laboratory distinguished lecture at the University of Canterbury (UC) campus on Wednesday night
which will consider the question: What if judges could understand forensic experts?
``Judges make errors, but these errors are not easily observed. After an acquittal the case is closed so it is difficult
to find out at a later date if the suspect was the perpetrator after all. Only rarely is a convicted suspect found to be
innocent. This lack of feedback means a judge can make the same errors during their career without ever knowing.
``In a laboratory experiment, we can create an environment in which such decisions can be compared with the correct
decision. In this way, we can find out what kind of errors are most likely and what we can do about it.
``What kind of mistakes do judges make? Will judges and forensic experts ever understand each other? What can we do to
improve the decisions of judges? How can economics experiments help?
``In criminal cases the task of the judge is foremost to transform the uncertainty about the facts into the certainty of
the verdict. Forensic research has become increasingly technical and forensic reports typically report conditional
probabilities.
``An important part of the job of judges is hypothesis testing (guilty or not guilty) but they have never received any
formal training in this in contrast to students in other academic disciplines.’’
In Professor Sonnemans’ country the government has plans reduce costs by decreasing the number of cases in which a team
of judges, instead of one judge, presides.
``We find that having more than one judge reduces error effectively. This does not mean that it is necessary to
deliberate about all cases. In simple cases many errors can be avoided by mechanical aggregation of independent
opinions, and deliberation has no added value.
``Discussion leads to less error in difficult cases. Although we provide no feedback about the quality of verdicts, it
improves individual decisions in subsequent cases,’’ Professor Sonnemans said. For details about the lecture: http://www.canterbury.ac.nz/wiw/
ENDS