Forensic Data Science Laboratory
Home Training	Continuing Professional Development Workshop Introduction to the likelihood ratio framework for evaluation of forensic evidence

---

Presenter

Prof Geoffrey Stewart Morrison

Target audiences

Forensic science practitioners



Forensic science researchers



Students of forensic science



Lawyers



Judges

Abstract

Among experts in forensic inference and statistics the likelihood ratio framework is widely regarded as the logically correct framework for evaluation of forensic evidence, but there is a great deal of misunderstanding about likelihood ratios among lawyers and forensic scientists.



The likelihood-ratio framework makes explicit the questions which must logically be addressed by the forensic scientist and considered by lawyers, judges, and trier’s of fact in assessing the work of the forensic scientist.



This workshop explains the logic of the likelihood-ratio framework in a way which is accessible to a broad audience and which does not require any prior knowledge of the framework. It uses intuitive examples and audience-participation exercises to gradually build a fuller understanding of the likelihood-ratio framework.

Presentation material

Slides



Didactic quiz

Please bring a copy of the didactic quiz with you to the workshop, an electronic copy on a laptop or tablet, or a printout on paper.

Comments from past participants

Participants frequently remark that, although they may have struggled in past attempts to understand the likelihood ratio framework, this workshop made it clear and easily understandable.


Interactive, small group, whole day workshop, plenty of time for questions, speaker was knowledgeable and funny. I can’t think of a negative point . Excellent all round.



Engagingly presented well structured workshop with the right mix between presentation and discussion.



I obtained great value from this workshop which was: Very well arranged. Structure was excellent. Pacing was good. Learning feedback opportunities were numerous. Facilities were excellent.



I liked the structure of the workshop - how we started with basic concepts and applied those to scientific data. The presentation was clear and very useful. I also liked the exercises after the presentation, which helped to put the theory into practice and test our knowledge. Highly enjoyable. I can’t think of any improvements!



The pace of the workshop was appropriate as it gives you time to think and develop the understanding. Content was also good as it included the application of the LR to various forensic type of evidence. Venue and catering were also good.



I liked the build up from assuming no knowledge to actually thinking about likelihood ratios. The examples were great and varied and easily relatable. It didn’t feel rushed or too slow. There was sufficient time to think and consume before moving on to the next bit. I loved the way the formulae were explained and progressed.



I thought that the workshop was overall very broad and informative - providing an overview of likelihood ratios while going through a few simple concrete examples. A strength of the workshop was that it was very interactive. It was nice to see how the likelihood ratio applied to forensic evidence contexts and working through examples helped me to understand and practice the concepts. I also thought that it was helpful to work through simple and fun examples to ease into the more complex forensic type problems. Great workshop overall!

Manager of a Forensic Laboratory:

I liked the simple and effective way the workshop was presented and discussed. It could have been a lot more statistical and formulaic but Geoff kept that to a bare minimum.

Head of the Forensic Science Division of a large Public Defender Office:

I have attended several presentations on the likelihood-ratio framework over the last few years. Yours was the first that actually made it understandable.

About the presenter

Prof Geoffrey Stewart Morrison is Director of the Forensic Data Science Laboratory at Aston University. His past appointments include Scientific Counsel, Office of Legal Affairs, INTERPOL. He is author of 100 refereed and invited publications. In a citation-based ranking, he is ranked in the top 0.35% of scientists in Legal & Forensic Medicine. He is Associate Editor, focusing on forensic inference and statistics, for the peer-reviewed journal Science & Justice. 2019–2025, he was Chair of the British Standards Institutionʼs Forensic Science Committee and was an active contributor to the development of the new international standard for forensic science, ISO 21043. More information about his work can be found at: http://geoff-morrison.net/

Dates (for on campus delivery)

For P-ACE LAB invitees: 2025-12-12



Future dates TBA

Venue (for on campus delivery)

For P-ACE LAB invitees on 2025-12-12: John Cadbury House – Aston University, 190 Corporation Street, Birmingham, B4 6QD, UK



Venues for future dates TBA