National Institute of

Standards and Technology

Technical	Colloquium

Quantifying	the	weight	of	forensic

evidence

May	5-6,	2016

(2016-04-29)	DRAFT PROGRAM

The National Institute for Standards and Technology (NIST) is happy to	announce the agenda for	the technical colloquium on

Quantification of the Weight of Forensic Evidence.	The purpose of the technical colloquium is to facilitate a	technical discussion about

theories and current	approaches and practices for	assigning the weight	of	evidence. Issues	related to statistical methods	for quantifying

the weight	of	evidence and their	introduction into courts of	law, are of	great	interest	and importance in forensic science. The

technical colloquium, which is part of the IBPC2016,	will be held May 5-6	at NIST	in Gaithersburg, Maryland.

@ NIST 

NIST has conducted	and	supported	forensic science research	for many decades, dating back to	1932, when	the FBI consulted	with	NIST

(then the National Bureau of	Standards) experts during the	establishment of the	FBI Laboratory. NIST	is a	co-chair of the National

Commission	on	Forensic Science, whose aims are to	enhance the practice and	improve the reliability of forensic science. The NIST	

Forensic Science	Research	Program coordinates research	in	disciplines such	as pattern	and	impression	evidence (fingerprint, shoeprint,

firearms), biology/DNA, drugs and toxicology, trace evidence/chemistry and digital and multimedia evidence. Additionally, NIST	has

established the	Organization of Scientific Area	Committees (OSAC) to support the	development and promulgation of forensic science	

consensus	documentary	standards	and guidelines, and to ensure that a sufficient scientific	basis	exists	for each discipline.		NIST also has

a	Forensic Science	Center of Excellence. The	Center for Statistics and Applications in Forensic Evidence, a	consortium led by Iowa	State

University supports NIST's efforts to advance the utility of probabilistic methods to enhance forensic analysis.

Organizers

Elham Tabassi, Reva Schwartz

NIST

Speakers: forensic scientists,

statisticians, lawyers,

practitioner

Target audience: forensic

scientists, researchers,

statisticians, lawyers,

practitioner

IBPC Conference, May 3-5 Satellite Session, May 5-6

International	Biometric	Performance Conference 2016

http://www.nist.gov/itl/iad/ig/ibpc2016.cfm

Technical Colloquium

Quantifying the weight of forensic evidence

Red Auditorium, NIST Green Auditorium, NIST

08:30	– 18:00 08:30	– 18:00

Registration https://appam.certain.com/profile/form/index.cfm?PKformID=0x2990790be

(IBPC2016 registrants are already registered for the TC) Registration Deadline: April

28,	2016.	All speakers and

attendees	must	register.

Hotels +	Logistics http://www.nist.gov/itl/iad/ig/ibpc-technical-colloquium.cfm

Maps +	Directions http://www.nist.gov/public_affairs/visitor/index.cfm

Colloquium Homepage http://www.nist.gov/itl/iad/ig/evidential_value.cfm
Thursday May 5 Green Auditorium Friday May 6 Portrait Room

0800	Registration 0800	Registration

0830	Welcome

Dr. Richard R.

introduction, goals, logistics

Cavanagh,	Director of the Special Programs Office,	NIST

0830	Overview of NIST

Susan Ballou,	Forensic

forensic research

Science program manager,	NIST

0900	Perspectives and Challenges from NIST	Involvement

National Institute of Standards and Technology

in	Forensic Science,	John Butler,	 0840	The interpretation	of DNA

Standards and	Technology

evidence,	John Buckleton,	National	Institute	of

0945	Legal,

Kaye,	Penn

Statistical,

	State	Law

and	Forensic Science Conceptions of the Weight of Evidence, David 0925: Quantitative Firearms and Toolmark Analysis: New Developments

Software,	Nicholas Petraco, John Jay College of	Criminal	Justice

and

1030 Break 1000	Break

1045 – What is probability,	Jim Wayman,	San	Jose	State	University 1030 A	new paradigm for forensic science and its implementation in forensic

voice	comparison,	Geoffrey Stewart Morrison and Ewald Enzinger,	Morrison

&	Enzinger, Independent Forensic Consultants

1130	Communicating Weight of Forensic Evidence Using a	LR: Whose prior, Whose

likelihoods,	and Whom are we kidding? Hari Iyer and	Steve	Lund,	National Institute

Standards and	Technology

of

1115	Discussion	Moderator: Joe Campbell, MIT Lincoln Laboratory

1200	Lunch	(on	your own) 1200	Lunch	(on	your own)

1330 Evaluating and Reporting Forensic Evidence	Using the

Challenges, Marjan Sjerps, Netherland Forensic Institute

LR Framework: Statistical 1330	Panel on	Similarity based LR models,	

Chair: Cedric Neumann,	South	Dakota	State	University

Panelists: Doug Armstrong, Marjan Sjerps , Hal Stern, Steve Lund

1400	Discussion

1430	Break 1500	Break

1500	New	approaches to	the quantification	of trace evidence for source identification,	

Danica Ommen,	Chris	Saunders (South	Dakota	State	University) and JoAnn Buscaglia,

FBI

1530	Panel on	LR Confidence interval,	

Chair: Chris Saunders, South	Dakota	State	University

Panelists: Danica Ommen, Marjan	Sjerps , Hal Stern, Hari Iyer

1530	Integrating Probabilistic Logic and Quantitative Data into Practice: Latent

Examination,	Henry Swofford, U.S. Army Criminal Investigation Laboratory

Print

1600	Discussion. Moderator Bill Thompson,	UC	Irvine 1700	Wrap up

1730	Adjourn 1730	Adjourn

		
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Panel on similarity based likelihood ratio 

Chair: Cedric Neumann, South Dakota State University 

Panelists: 

* Doug Armstrong, South Dakota State University 

* Marjan Sjerps, Netherland Forensic Institute 

* Hal Stern, University of California at Irvine/CSAFE 

* Steven Lund, National Institute of Standards and Technology 

The legal and scientific push towards the statistical quantification of the weight of forensic evidence is impeded by the complexity the various evidence 

types encountered on crime scenes. Complex forms of forensic evidence, such as fingerprints, tool marks, shoe prints or chemical profiles often live in 

high dimensional and heterogenous spaces. The need to reduce the complexity of the models has resulted in the apparition of a series of ad-hoc measures 

of the probative value of some forms of forensic evidence, which rely, by proxy, on the level of similarity (or score) between pairs of objects, instead of 

being directly based on sets of measurements of these objects. The appropriateness of these ad-hoc methods has been challenged at several occasions. 

The challenges are based on the argument that these methods do not address the questions of interest to forensic scientists and courts, and do not provide 

a coherent (in the statistical sense) way of updating prior information in a Bayesian framework. Proponents of these methods have made the argument 

that since probabilities are inherently subjective (or personal), the probative values calculated by these methods were merely an expression of the 

personal weight assigned by the forensic scientist to the evidence, and therefore were acceptable. The aim of this panel is to discuss the appropriateness 

of score-based methods as a mean to quantify and report the weight of forensic evidence, and the place of these methods in a coherent Bayesian 

paradigm. 

Panel on the use of interval quantifications for the value of forensic evidence 

Chair: Chris Saunders, South Dakota state university 

Panelists: 

* Danica Ommen, South Dakota State University 

* Hari Iyer, National Institute of Standards and Technology 

* Marjan Sjerps, Netherland Forensic Institute 

* Hal Stern, University of California at Irvine/CSAFE 

At the 2012 ENFSI meeting, Ivo Alberink and James Curran proposed an interval quantification of the value of evidence. This led to a lively discussion 

on the reasonableness of these intervals for the logical and coherent interpretation of forensic evidence. Geoffrey Morrison arranged for a series of short 

presentations on this issue at the 2015 ENFSI meeting. This resulted in a series of papers published in Law, Probability, and Risk arguing the validity of 

using these intervals in the formal subjective Bayesian paradigm for evidence interpretation. It appears that the two groups arguing for and against the 

use of intervals are talking past each other, with one group taking a frequentist stance (or the likelihood paradigm of Edwards and Royall) and the other 

taking a completely subjective Bayesian view. This panel will be focused on discussing the possibility of and developing a common foundation among 

the participants to be able to discuss what an interval estimate of the likelihood ratio actually means and its relationship to the formal value of evidence 

as characterized by the Bayes Factor.