Activity level DNA evidence evaluation: on propositions addressing the actor or the activity

More often than not, the source of DNA traces found at a crime scene is not disputed, but the activity or timing of events that resulted in their transfer is. As a consequence, practitioners are increasingly asked to assign a value to DNA evidence given propositions about activities provided by prosecution and defense counsel. Given that the dispute concerns the nature of the activity that took place or the identity of the actor that carried out the activity, several factors will determine how to formulate the propositions. Determining factors are (1) whether defense claims the crime never took place, (2) whether defense claims someone other than the accused (either an unknown individual or a known person) performed the criminal activity, and (3) whether it is claimed and disputed that the suspect performed an alternative, legitimate activity or has a relation to the victim, the object, or the scene of crime that implies a legitimate interaction. Addressing such propositions using Bayesian networks, we demonstrate the effects of the various proposition sets on the evaluation of the evidence.Criminal Justice: Legitimacy, accountability, and effectivit

Plaats delict-onderzoek met vooruitziende blik: Anticiperen op alternatieve scenario’s tijdens het sporenonderzoek op de plaats delict

Criminal Justice: Legitimacy, accountability, and effectivit

De waarheidsvinding naar een hoger niveau

Oratie uitgesproken door Prof. dr. ir. Charles E.H. Berger bij de aanvaarding van de hernieuwde benoeming tot bijzonder hoogleraar in de Criminalistiek aan de Universiteit Leiden vanwege de Stichting Criminalistiek op vrijdag 3 februari 2017Oratie uitgesproken door Prof. dr. ir. Charles E.H. Berger bij de aanvaarding van de hernieuwde benoeming tot bijzonder hoogleraar in de Criminalistiek aan de Universiteit Leiden vanwege de Stichting Criminalistiek op vrijdag 3 februari 2017FdR – Publicaties zonder aanstelling Universiteit Leide

Conference report: International Conference on Forensic Inference and Statistics 2014

Criminal Justice: Legitimacy, accountability, and effectivit

Interpreting Evidence of Torture

Criminal Justice: Legitimacy, accountability, and effectivit

Conference report: International Conference on Forensic Inference and Statistics 2014

Criminal Justice: Legitimacy, accountability, and effectivit

How clear is transparent? Reporting expert reasoning in legal cases

Experts providing evidence in legal cases are universally recommended to be transparent, particularly in their reasoning, so that legal practitioners can critically check whether the conclusions are adequately supported by the results. However, when exploring the practical meaning of this recommendation it becomes clear that people have different things in mind. The UK appeal court case R v T painfully exposes the different views. In this article we argue that there can be a trade-off between clarity and transparency, and that in some cases it is impossible for the legal practitioner to be able to followthe expert’s reasoning in full detail because of the level of complexity. All that can be expected in these cases is that the legal practitioner is able to understand the reasoning up to a certain level. We propose that experts should only report the main arguments, but must make this clear and provide further details on request. Reporting guidelines should address the reasoning in more detail. Legal practitioners and scientists should not be telling each other what to do in the setting of a legal case, but in other settings more discussion will be beneficial to both. We see the likelihood ratio framework and Bayesian networks as tools to promote transparency and logic. Finally, we argue that transparency requires making clear whether a conclusion is a consensus and reporting diverging opinions on request

Discussion paper: Reaction to Hamer and Thompson in LPR

The Hamer contribution reveals a lot of the common misperceptions surrounding the issues in R v. T. While the paper risks adding to the confusion of the uninformed reader, we will use it to list and address such misperceptions in this reaction. We acknowledge that the author will in some cases have described misconceptions held by others rather than his own, although this is not always clear

Response to “A study of the perception of verbal expressions of the strength of evidence”

We would like to respond to the recent paper “Understanding forensic expert evaluative evidence: A study of the perception of verbal expressions of the strength of evidence”, by Arscott et al.. We agree that a verbal expression of the strength of evidence can be interpreted in varying ways. Not only by the people that read them, but also by those that express them. It is also possible that different verbal expressions are interpreted in the same way by different readers or reporting scientists. This is the reason that the Association of Forensic Science Providers (AFSP) and the European Network of Forensic Science Institutes (ENFSI) have published guidelines that call for forensic institutes to provide verbal scales and numerically define the verbal expressions therein. This, at least formally, solves the issue of the perception of intended strength of evidence.Criminal Justice: Legitimacy, accountability, and effectivit