Forensic Evaluation Ltd
Dr Geoffrey Stewart Morrison, Director and Forensic Consultant

last update

  • I provide consulting on:

    • forensic speech science

    • forensic inference and statistics

  • I provide case-specific forensic analysis, advice, and/or critique of other’s reports

    • as a testifying witness or a non-testifying advisor

    • at admissibility hearings, at trial, and at appeal

  • I provide training for lawyers and forensic scientists

  • I work in a paradigm which includes:

    • Evaluation of strength of evidence using the likelihood ratio framework.

      • Recognised by leading forensic statisticians as the logically correct framework for evaluation of strength of evidence.
European Network of Forensic Science Institutes (2015) Guideline for evaluative reporting in forensic science

“The reporting of the value of scientific findings shall conform to four requirements: Balance, Logic, Robustness and Transparency.”

“Reporting practice should conform to these logical principles. This framework for evaluative reporting applies to all forensic science disciplines.The likelihood ratio measures the strength of support the findings provide to discriminate between propositions of interest. It is scientifically accepted, providing a logically defensible way to deal with inferential reasoning.”

    • Calculation of strength of evidence, on the basis of relevant data, quantitative measurements, and statistical models.

      • Such approaches are transparent, replicable, and resistant to cognitive bias.

    • Empirical testing of the validity and reliability of the system used to assess the strength of evidence in the case.

      • Testing performed under conditions reflecting those of the case.

      • Such testing is the only way to determine how well a method and its implementation work.
President Obama’s Council of Advisors on Science and Technology (PCAST) September 2016 Report on Forensic science in criminal courts: Ensuring scientific validity of feature-comparison methods, page 6:

“neither experience, nor judgment, nor good professional practices (such as certification programs and accreditation programs, standardized protocols, proficiency testing, and codes of ethics) can substitute for actual evidence of foundational validity and reliability. The frequency with which a particular pattern or set of features will be observed in different samples, which is an essential element in drawing conclusions, is not a matter of ‘judgment.’ It is an empirical matter for which only empirical evidence is relevant. Similarly, an expert’s expression of confidence based on personal professional experience or expressions of consensus among practitioners about the accuracy of their field is no substitute for error rates estimated from relevant studies. For forensic feature-comparison methods, establishing foundational validity based on empirical evidence is thus a sine qua non. Nothing can substitute for it.”

  • I have casework experience in:
    • Australia (NSW, QLD, SA, VIC, WA)
    • Canada
    • China
    • Northern Ireland
    • Sweden
    • United States (Federal, CO, MN)

  • I conduct forensic analyses in forensic speech science:

    • forensic voice comparison
      • where the court wants to determine whether the voice of a speaker on an audio recording was produced by a particular known speaker or by some other speaker

    • disputed-utterance analysis
      • where the court wants to determine what a speaker said at some point on an audio recording

    • My experience includes conducting analyses, submitting reports in both criminal and civil proceedings, and testifying in court.

  • I also provide critiques of reports submitted by others.

    • My experience includes submitting written critiques and testifying in court.

    • My experience includes advising the defence in relation to a US Federal Court Daubert hearing on the admissibility of forensic voice comparison testimony tendered by the prosecution.

    • Example of a critique written for a journalistic case

    • Lawyers who are concerned about the scientific validity of a forensic speech science report submitted by another expert should definitely contact me.

  • I provide testimony related to a listener’s abilities to recognise a speaker by the sound of their voice.

    • Sometimes instead of commissioning a forensic voice comparison report, a party in a court case attempts to rely on a non expert, such as a police officer, saying that they recognised a speaker’s voice.

    • Research has identified a number of factors that may make listeners better or worse at identifying speakers.

    • A key research finding is that people think that they and others are better at identifying speakers than they really are.

    • My experience includes submitting written reports and testifying in court.

  • I also provide informational reports designed to educate the court about speaker recognition in general.

    • My experience includes submitting a written report in relation to a civil case.


I provide training for forensic scientists, lawyers, judges, and others.

Training can be specific to forensic speech science, or can cover evaluation of forensic evidence in general.

Training will be tailored depending on the needs of the client.

Training can be provided in English or Spanish. / Los talleres se puede impartir en inglés o español.

Below are outlines of introductory workshops.

  • Introduction to logical reasoning for the evaluation of forensic evidence

    • Slides:

    • Audience: forensic scientists and/or lawyers

      This half-day workshop provides an introduction to the likelihood-ratio framework for the evaluation and interpretation of forensic evidence.

      There is a great deal of misunderstanding and confusion about the likelihood-ratio framework among lawyers, judges, 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.

      The workshop also includes discussion of common logical fallacies.

      Other workshops Dr Morrison presents generally assume familiarity with the material presented in this workshop.

  • Calculating the strength of forensic evidence, and testing the validity and reliability of forensic-evaluation systems

    • Audience: forensic scientists or lawyers (different depth of coverage and focus depending on the audience)

      This half-day workshop provides an introduction to topics such as the calculation of forensic likelihood ratios on the basis of relevant data, quantitative measurements, and statistical models, and an introduction to empirically assessing the validity and reliability of forensic-evaluation systems.

      Some of the topics listed below can also be presented as stand alone tutorials.

      Audience members are assumed to already have a basic understanding of the logic of the likelihood-ratio framework, e.g., by having participated in my workshop “Introduction to logical reasoning for the evaluation of forensic evidence”.

      Topics covered may include:

      • basic statistical models for calculating likelihood ratios

      • calibrating forensic-evaluation systems

      • empirically testing the validity and reliability of forensic-evaluation systems


About Dr Morrison
Morrison is one of the leading thinkers in the world about problems of forensic inference.

Few have his ability to understand and explain forensic statistics.

Prof William C Thompson
School of Law, and Department of Criminology, Law & Society, University of California Irvine
Co-counsel for OJ Simpson in his criminal trial in Los Angeles, 1994–1995
Originator of the terms “prosecutor’s fallacy” and “defense attorney’s fallacy”

Morrison has a very nice writing style and I think he has phrased some of the fundamental matters in a way that is more clearly put than I have ever seen. I think he has done a masterly job.

Dr John S Buckleton
Principle Scientist, ESR Forensics, Auckland, New Zealand
Commenting on Morrison (2010) Forensic voice comparison, Expert Evidence Series.

In addition to my consulting work, I am:

  • Associate Professor of Forensic Speech Science, Centre for Forensic Linguistics, Aston University

My previous appointments include:

  • Simons Foundation Visiting Fellow, Probability and Statistics in Forensic Science Programme, Isaac Newton Institute for Mathematical Sciences

  • Scientific Counsel, Office of Legal Affairs, INTERPOL

  • Adjunct Professor, Department of Linguistics, University of Alberta

  • Director, Forensic Voice Comparison Laboratory, School of Electrical Engineering & Telecommunications, University of New South Wales

I am also:

  • Fellow of the Chartered Society of Forensic Sciences

I have also been:

I am involved in the development of standard for foresnic science via membership in commitees, subcomittees, and working groups of:

  • British Standards Institute (BSI)

  • International Organization for Standardization (ISO)

  • Organization of Scientific Area Comittees for Forensic Science (OSAC)

I have authored more than 50 peer-reviewed journal articles, law review articles, book chapters, and conference proceedings papers.

I have provided training and/or research and development services to lawyers and forensic laboratories in North and South America, Europe, Australasia, and Asia.

For more about my work see:

Recommended reading

The following publications provide introductions to forensic speech science and evaluation of forensic evidence. They should be accessible to a broad audience including lawyers.


  • An initial consultation up to half an hour is free.

  • Send me an e-mail with your contact information and I will call you via skype or telephone as soon as I can.

    • e-mail address:

      geoff hyphen morrison at forensic hyphen evaluation dot net

  • Effective mid 2017:

    • Longer term reseach & development and training are provided through Aston University.

    • Casework and shorter term consulting are provided through Forensic Evaluation Ltd.