A guideline for the validation of likelihood ratio methods used for forensic evidence evaluation

Didier Meuwly, Daniel Ramos, Rudolf Haraksim

  • 3 Citations

Abstract

This Guideline proposes a protocol for the validation of forensic evaluation methods at the source level, using the Likelihood Ratio framework as defined within the Bayes’ inference model. In the context of the inference of identity of source, the Likelihood Ratio is used to evaluate the strength of the evidence for a trace specimen, e.g. a fingermark, and a reference specimen, e.g. a fingerprint, to originate from common or different sources. Some theoretical aspects of probabilities necessary for this Guideline were discussed prior to its elaboration, which started after a workshop of forensic researchers and practitioners involved in this topic. In the workshop, the following questions were addressed: ‘‘which aspects of a forensic evaluation scenario need to be validated?’’, ‘‘what is the role of the LR as part of a decision process?’’ and ‘‘how to deal with uncertainty in the LR calculation?’’. The questions: ‘‘what to validate?’’ focuses on the validation methods and criteria and ‘‘how to validate?’’ deals with the implementation of the validation protocol. Answers to these questions were deemed necessary with several objectives. First, concepts typical for validation standards [1], such as performance characteristics, performance metrics and validation criteria, will be adapted or applied by analogy to the LR framework. Second, a validation strategy will be defined. Third, validation methods will be described. Finally, a validation protocol and an example of validation report will be proposed, which can be applied to the forensic fields developing and validating LR methods for the evaluation of the strength of evidence at source level under the following propositions: H1/Hss: The trace and reference originate from the same source. H2/Hds: The trace and reference originate from different sources.
Original languageEnglish
Pages (from-to)142-153
Number of pages12
JournalForensic science international
DOIs
StatePublished - 2017

Fingerprint

Education
Dermatoglyphics
Uncertainty

Keywords

  • METIS-317221
  • IR-100642
  • Automatic interpretation method
  • Method validation
  • Validation report
  • Strength of evidence Accreditation
  • EWI-27063
  • SCS-Safety

Cite this

Meuwly, Didier; Ramos, Daniel; Haraksim, Rudolf / A guideline for the validation of likelihood ratio methods used for forensic evidence evaluation.

In: Forensic science international, 2017, p. 142-153.

Research output: Scientific - peer-reviewArticle

@article{9f94fcdaec224e8f947afef3f42b9d0e,
title = "A guideline for the validation of likelihood ratio methods used for forensic evidence evaluation",
abstract = "This Guideline proposes a protocol for the validation of forensic evaluation methods at the source level, using the Likelihood Ratio framework as defined within the Bayes’ inference model. In the context of the inference of identity of source, the Likelihood Ratio is used to evaluate the strength of the evidence for a trace specimen, e.g. a fingermark, and a reference specimen, e.g. a fingerprint, to originate from common or different sources. Some theoretical aspects of probabilities necessary for this Guideline were discussed prior to its elaboration, which started after a workshop of forensic researchers and practitioners involved in this topic. In the workshop, the following questions were addressed: ‘‘which aspects of a forensic evaluation scenario need to be validated?’’, ‘‘what is the role of the LR as part of a decision process?’’ and ‘‘how to deal with uncertainty in the LR calculation?’’. The questions: ‘‘what to validate?’’ focuses on the validation methods and criteria and ‘‘how to validate?’’ deals with the implementation of the validation protocol. Answers to these questions were deemed necessary with several objectives. First, concepts typical for validation standards [1], such as performance characteristics, performance metrics and validation criteria, will be adapted or applied by analogy to the LR framework. Second, a validation strategy will be defined. Third, validation methods will be described. Finally, a validation protocol and an example of validation report will be proposed, which can be applied to the forensic fields developing and validating LR methods for the evaluation of the strength of evidence at source level under the following propositions: H1/Hss: The trace and reference originate from the same source. H2/Hds: The trace and reference originate from different sources.",
keywords = "METIS-317221, IR-100642, Automatic interpretation method, Method validation, Validation report, Strength of evidence Accreditation, EWI-27063, SCS-Safety",
author = "Didier Meuwly and Daniel Ramos and Rudolf Haraksim",
note = "eemcs-eprint-27063",
year = "2017",
doi = "10.1016/j.forsciint.2016.03.048",
pages = "142--153",
journal = "Forensic science international",
issn = "0379-0738",
publisher = "Elsevier Ireland Ltd",

}

A guideline for the validation of likelihood ratio methods used for forensic evidence evaluation. / Meuwly, Didier; Ramos, Daniel; Haraksim, Rudolf.

In: Forensic science international, 2017, p. 142-153.

Research output: Scientific - peer-reviewArticle

TY - JOUR

T1 - A guideline for the validation of likelihood ratio methods used for forensic evidence evaluation

AU - Meuwly,Didier

AU - Ramos,Daniel

AU - Haraksim,Rudolf

N1 - eemcs-eprint-27063

PY - 2017

Y1 - 2017

N2 - This Guideline proposes a protocol for the validation of forensic evaluation methods at the source level, using the Likelihood Ratio framework as defined within the Bayes’ inference model. In the context of the inference of identity of source, the Likelihood Ratio is used to evaluate the strength of the evidence for a trace specimen, e.g. a fingermark, and a reference specimen, e.g. a fingerprint, to originate from common or different sources. Some theoretical aspects of probabilities necessary for this Guideline were discussed prior to its elaboration, which started after a workshop of forensic researchers and practitioners involved in this topic. In the workshop, the following questions were addressed: ‘‘which aspects of a forensic evaluation scenario need to be validated?’’, ‘‘what is the role of the LR as part of a decision process?’’ and ‘‘how to deal with uncertainty in the LR calculation?’’. The questions: ‘‘what to validate?’’ focuses on the validation methods and criteria and ‘‘how to validate?’’ deals with the implementation of the validation protocol. Answers to these questions were deemed necessary with several objectives. First, concepts typical for validation standards [1], such as performance characteristics, performance metrics and validation criteria, will be adapted or applied by analogy to the LR framework. Second, a validation strategy will be defined. Third, validation methods will be described. Finally, a validation protocol and an example of validation report will be proposed, which can be applied to the forensic fields developing and validating LR methods for the evaluation of the strength of evidence at source level under the following propositions: H1/Hss: The trace and reference originate from the same source. H2/Hds: The trace and reference originate from different sources.

AB - This Guideline proposes a protocol for the validation of forensic evaluation methods at the source level, using the Likelihood Ratio framework as defined within the Bayes’ inference model. In the context of the inference of identity of source, the Likelihood Ratio is used to evaluate the strength of the evidence for a trace specimen, e.g. a fingermark, and a reference specimen, e.g. a fingerprint, to originate from common or different sources. Some theoretical aspects of probabilities necessary for this Guideline were discussed prior to its elaboration, which started after a workshop of forensic researchers and practitioners involved in this topic. In the workshop, the following questions were addressed: ‘‘which aspects of a forensic evaluation scenario need to be validated?’’, ‘‘what is the role of the LR as part of a decision process?’’ and ‘‘how to deal with uncertainty in the LR calculation?’’. The questions: ‘‘what to validate?’’ focuses on the validation methods and criteria and ‘‘how to validate?’’ deals with the implementation of the validation protocol. Answers to these questions were deemed necessary with several objectives. First, concepts typical for validation standards [1], such as performance characteristics, performance metrics and validation criteria, will be adapted or applied by analogy to the LR framework. Second, a validation strategy will be defined. Third, validation methods will be described. Finally, a validation protocol and an example of validation report will be proposed, which can be applied to the forensic fields developing and validating LR methods for the evaluation of the strength of evidence at source level under the following propositions: H1/Hss: The trace and reference originate from the same source. H2/Hds: The trace and reference originate from different sources.

KW - METIS-317221

KW - IR-100642

KW - Automatic interpretation method

KW - Method validation

KW - Validation report

KW - Strength of evidence Accreditation

KW - EWI-27063

KW - SCS-Safety

U2 - 10.1016/j.forsciint.2016.03.048

DO - 10.1016/j.forsciint.2016.03.048

M3 - Article

SP - 142

EP - 153

JO - Forensic science international

T2 - Forensic science international

JF - Forensic science international

SN - 0379-0738

ER -