A Comment on the PCAST Report: Skip the 'Match'/'Non-Match' Stage

Forensic Science International (Forthcoming)

6 Pages Posted: 31 Oct 2016

See all articles by Geoffrey Morrison

Geoffrey Morrison

Forensic Evaluation Ltd; Centre for Forensic Linguistics, Aston University

David H. Kaye

The Pennsylvania State University (University Park) – Penn State Law; Arizona State University - Sandra Day O'Connor College of Law - School of Life Science

David J. Balding

Imperial College London

Duncan Taylor

Flinders University

Philip Dawid

University of Cambridge

Colin Aitken

University of Edinburgh

Simone Gittelson

Government of the United States of America - National Institute of Standards and Technology (NIST)

Grzegorz Zadora

University of Silesia in Katowice

Bernard W. Robertson

Independent

Sheila Willis

Forensic Science Ireland

Susan Pope

Independent

Martin Neil

University of London - Queen Mary - Computer Science

Kristy A Martire

University of New South Wales (UNSW)

Amanda B. Hepler

Innovative Decisions, Inc.

Richard Gill

Leiden University

Allan Jamieson

The Forensic Institute

Jacob de Zoete

University of Amsterdam, Mathematics, Students

Brent Ostrum

CBSA - LSSD

Amke Caliebe

University of Kiel

Date Written: October 25, 2016

Abstract

This letter comments on the report “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-comparison Methods” released in September 2016, by the President’s Council of Advisors on Science and Technology (PCAST). The report advocates a two-stage procedure for evaluation of forensic evidence. The first stage is a “match”/“non-match” determination, and the second stage is an empirical assessment of sensitivity (correct acceptance) and false alarm (false acceptance) rates. Almost always, quantitative data from feature-comparison methods are continuously-valued and have within-source variability. We explain why a two-stage procedure is not appropriate for this type of data, and recommend more appropriate statistical procedures.

Suggested Citation

Morrison, Geoffrey and Kaye, David H. and Balding, David J. and Taylor, Duncan and Dawid, Alexander and Aitken, Colin and Gittelson, Simone and Zadora, Grzegorz and Robertson, Bernard W. and Willis, Sheila and Pope, Susan and Neil, Martin and Martire, Kristy A and Hepler, Amanda B. and Gill, Richard and Jamieson, Allan and de Zoete, Jacob and Ostrum, Brent and Caliebe, Amke, A Comment on the PCAST Report: Skip the 'Match'/'Non-Match' Stage (October 25, 2016). Forensic Science International (Forthcoming). Available at SSRN: https://ssrn.com/abstract=2860440

Centre for Forensic Linguistics, Aston University ( email )

Aston Triangle
Birmingham, B4 7ET
United Kingdom

HOME PAGE: http://geoff-morrison.net/

David H. Kaye

The Pennsylvania State University (University Park) – Penn State Law

Lewis Katz Building
University Park, PA 16802
United States

HOME PAGE: http://www.personal.psu.edu/dhk3/index.htm

Arizona State University - Sandra Day O'Connor College of Law - School of Life Science ( email )

111 E Taylor St.
Phoenix, AZ 85004
United States

HOME PAGE: http://www.personal.psu.edu/dhk3/index.htm

David J. Balding

Imperial College London ( email )

Building and Campus Norfolk Place
St Mary's Campus
United Kingdom
+44 (0)20 7594 3309 (Phone)

Duncan Taylor

Flinders University ( email )

GPO Box 2100
Adelaide S.A. 5001, SA 5063
Australia

Alexander Dawid

University of Cambridge ( email )

King's Parade
Cambridge, CB3 0DS
United Kingdom

HOME PAGE: http://www.statslab.cam.ac.uk/~apd/

Colin Aitken

University of Edinburgh

Old College
South Bridge
Edinburgh, Scotland EH8 9JY
United Kingdom

Simone Gittelson

Government of the United States of America - National Institute of Standards and Technology (NIST) ( email )

Gaithersburg, MD 20899-8910
United States

Grzegorz Zadora

University of Silesia in Katowice ( email )

ul. Okólna 89F
Częstochowa, 42-200
Poland

Bernard W. Robertson

Independent ( email )

No Address Available

Sheila Willis

Forensic Science Ireland ( email )

Garda HQ, Phoenix Park
Dublin
Ireland

Susan Pope

Independent ( email )

No Address Available

Martin Neil

University of London - Queen Mary - Computer Science ( email )

Mile End Road
London, London E1 4NS
United Kingdom
44-20-686-7882 (Phone)
44-20-8980-6533 (Fax)

Kristy A Martire

University of New South Wales (UNSW) ( email )

Kensington
High St
Sydney, NSW 2052
Australia

Amanda B. Hepler

Innovative Decisions, Inc.

8230 Old Courthouse Rd #460
Vienna, VA
United States

Richard Gill

Leiden University

Postbus 9500
Leiden, 2300 RA
Netherlands

Allan Jamieson

The Forensic Institute ( email )

Glasgow, Scotland
United Kingdom

Jacob De Zoete

University of Amsterdam, Mathematics, Students ( email )

Amsterdam
Netherlands

Brent Ostrum

CBSA - LSSD ( email )

Laboratory and Scientific Support Directorate
79 Bentley Avenue
Ottawa, Ontario K2E 6T7
Canada

Amke Caliebe

University of Kiel ( email )

Hans Detlev Prien Strabe
24106
Kiel, 1
Germany

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