'itis simply wrong in principle for an expert to fail to set out the way in whichhe has reached his conclusion in his report….usinga Bayesian approach…to formulate opinions placed before a jury...

Crime
MSc Forensics: Criminal Litigation
Success of criminal courts in understanding the Bayesian approach
Crime
Introduction to Bayesian approach
The criminal justice system plays an essential role in the present society since it helps
ensure the creation and establishment of an appropriate social institution. Social institution refers
to the group or set of norms set up by the society which help determine as to what kind of
behavior is right and what kind of behavior is wrong. It also refers to a group of social positions
which define the role of a person in the society. It is a system of values in the society (Foreman,
L.A; Smith, A.F.M. and Evett, I.W, 1997).
The Bayesian approach focuses on providing the jury a rational and unbiased method of
putting all of the evidence together and the usage of probability based on the Bayer's rule is
instrumental in the process of considering all of the possible events. In case of Bayesian
approach to resolve a court case, subjective probability is used for the purpose of updating
beliefs and focusing on all of the possibilities. This helps in creating a holistic approach towards
resolving a case. It involves subjective statistics and helps in analyzing the various possibilities
in a case before providing a legal interpretation and verdict to it (Dawid, A.P. and Mortera, J,
1996).
In case of a court case there are several parties involved and this leads to there being a
need for complete evaluation of all of the possibilities. It is essential that the court administrators
consider each of the possibility and the point of view of all of the parties and stakeholders
involved. The Bayesian approach has been known to minimize errors in court justice as statistics,
probability and mathematics gets involved in the process of judgment (Jim Albert, 2009).
Importance of Bayesian approach
The Bayesian approach is quite important in the processes of judgment. It helps associate
every single possibility with a probability and brings in practicality in the judgment process
(Dawid, A.P, 2001). It helps consider the points of view of each of the parties involved and helps
rationality being combined with a mathematical formula thus bringing in precision in court
rulings. It helps in the process of bringing in objectivity in the completely subjective decision
process in court rulings. Bayesian approach has been instrumental in giving a new dimension to
several cases and this can be of great utility in ensuring better support from the judicial system of
a nation to its citizens (Dawid, A.P. and Mortera, J, 1996).
Implementation and extent of understanding by the courts
The present day courts have been using the Bayesian approach as a supporting tool in the
judgment process. They have been able to use it as a toll that helps evaluate multiple aspects of a
case based on a formula. There has never been complete dependence on the Bayesian approach
and rationality has always been prioritized in case of a court ruling but the usage of the Bayesian
approach has also been instrumental in evaluating the bias of a judgment (Robertson, B. and
Vignaux, G.A, 1995).
Crime
In case of the Bayesian approach, the process involved is the inclusion of a formula
where in multiple possibilities are considered along with allocating probabilities to each of these
possibilities based on rationality and evaluation criteria. Now in case the probabilities associated
are biased, then it may result in a biased judgment. But if these probabilities are correctly
associated with each of the possibilities and experts are involved in the process it can help ensure
appropriate direction and help in making a court judgment (Foreman, L.A; Smith, A.F.M. and
Evett, I.W, 1997).
This tool is a contemporary one and is used conservatively in very few instances as the
main basis for a court ruling. The main reason for this is that the case approach and constitutional
laws are the basis for judgments in most of the cases. In this way there is minimal usage of the
Bayesian approach of judgment in the present criminal and judicial system. As the Bayesian
approach has multiple shortcomings, this results in several issues in its application and so it is
not being used extensively in the present judicial system. It is being used just as a complimentary
tool for evaluation of the bias and righteousness of a judgment (Jim Albert, 2009).
Moreover as it involves and requires experts to apply the formula as it is complicated and
allocation of probabilities, it results in a complex approach to court rulings where in the
rationality and basis of probability allocation becomes questionable (Raymond J. Solomonoff",
Peter Gacs, Paul M. B. Vitanyi, 2011). The extent to which an expert or a statistician can
understand the judgment and criminal processes is questionable. In this way there are multiple
issues that are to be considered while applying and implementing the Bayesian approach thus
making it essential to understand the right usage of this approach. It cannot be utilized in all of
the cases and there needs to be appropriate evaluation on where to apply the Bayesian approach.
It involves the considerations of the need of the case, its objectivity, subjectivity, factors
involved, parties involved, expertise available and appropriateness as well as synchronization
with rationality (Samuel Rathmanner and Marcus Hutter, 2011).
Issues in the usage of Bayesian approach
The main reason for Bayesian approach not having been implemented extensively in the
judicial system, especially with relation to criminal cases is that there have been several
shortcomings in the Bayesian approach as well as its acceptance. Firstly since it is a
mathematical approach, it is difficult to find judges who are comfortable with its usage and are
aware of the ways in which they can be implemented...