Artificial Intelligence and Law

, Volume 21, Issue 2, pp 221–252 | Cite as

Modeling the forensic two-trace problem with Bayesian networks

  • Simone Gittelson
  • Alex Biedermann
  • Silvia Bozza
  • Franco Taroni


The forensic two-trace problem is a perplexing inference problem introduced by Evett (J Forensic Sci Soc 27:375–381, 1987). Different possible ways of wording the competing pair of propositions (i.e., one proposition advanced by the prosecution and one proposition advanced by the defence) led to different quantifications of the value of the evidence (Meester and Sjerps in Biometrics 59:727–732, 2003). Here, we re-examine this scenario with the aim of clarifying the interrelationships that exist between the different solutions, and in this way, produce a global vision of the problem. We propose to investigate the different expressions for evaluating the value of the evidence by using a graphical approach, i.e. Bayesian networks, to model the rationale behind each of the proposed solutions and the assumptions made on the unknown parameters in this problem.


Evaluation of evidence Value of the evidence Graphical probability models Bayesian networks Two-trace problem 



This research was supported by the Swiss National Science Foundation grant n° 100014-122601/1.


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Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Simone Gittelson
    • 1
  • Alex Biedermann
    • 1
  • Silvia Bozza
    • 2
  • Franco Taroni
    • 1
  1. 1.Institut de Police Scientifique, Ecole des Sciences CriminellesUniversité de LausanneLausanneSwitzerland
  2. 2.Dipartimento di EconomiaUniversità Ca’ Foscari di VeneziaVeneziaItaly

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