Professor Marjan Sjerps accepts professorship
On Friday 4 November, Professor Marjan Sjerps gave her inaugural lecture at the University of Amsterdam, entitled ‘Evidential value: “Force 10”, full steam ahead'.
Marjan Sjerps, professor in Forensic Statistics, is to combine this professorship with her work as principal scientist and statistician at the Netherlands Forensic Institute (NFI) in The Hague. During her lecture she will outline the image that the general public have of forensic science: the image portrayed by popular TV series like ‘CSI’, in which items of evidence such as DNA profiles, fingerprints and shoe traces are collected at a crime scene and used during detection work and in court. Professor Sjerps’ lecture will start where the TV series ends, namely with the key question of what the evidential value is of the observations.
This question has everything to do with probability reasoning. Forensic statisticians have developed a framework, the Bayesian framework, which implies that you can measure evidential value using the quotient of two chances. This framework is a way of thinking which is generally applicable, including, for example, in the legal or medical domain. It enables the evidential value to be determined in a structured and transparent manner. This offers significant benefits in complicated situations in which, for example, someone is selected as a suspect precisely on the basis of evidence, or in situations in which the evidential value is a combination of observations. The ability to calculate the evidential value on the basis of hard data from random checks, databases and experiments leads to more objective conclusions, which are also more effectively substantiated. If such data is unavailable, the framework is extremely useful as a basis for structuring the probability reasoning in verbal terms.
Forensic Statistics
The Forensic Statistics chair at the University of Amsterdam, which Professor Sjerps will hold in the coming years, is located at the Korteweg de Vries Institute for Mathematics at the Faculty of Natural Sciences, Mathematics and Informatics. A scientific basis is important for forensic research. As far as university education is concerned, the social relevance of forensic research is another advantage. The combination of Marjan Sjerps’ professorship and her work at the NFI therefore generates significant added value for both the university and the NFI.
Marjan Sjerps is researching the applications of statistics and probability in forensic science and criminal law. This includes the interpretation and evaluation of (forensic) evidence. This field is also referred to as forensic statistics. Her core research questions are: How can a (forensic) researcher determine the evidential value of his research results? How can he then report on this evidential value to the police or judicial authorities? What is the evidential value of a combination of different items of evidence?
Forensic statistics considers these questions on the basis of mathematical probability models. This produces a mix of new applications of statistical techniques, the development of new methods, and fundamental research. This mix is relevant on both a scientific and practical level.