A more straightforward derivation of the LR for a database search.

Matching DNA profiles of an accused person and a crime scene trace are one of the most common forms of forensic evidence. A number of years ago the so-called 'DNA controversy' was concerned with how to quantify the value of such evidence. Given its importance, the lack of understanding of such a basic issue was quite surprising and concerning. Deriving the equation for the likelihood ratio of a DNA database match in a much more direct and simple way is the topic of this paper. As it is much easier to follow it is hoped that this derivation will contribute to the understanding.

[1]  D J Balding,et al.  Evaluating DNA profile evidence when the suspect is identified through a database search. , 1996, Journal of forensic sciences.

[2]  F. Taroni,et al.  A Bayesian network approach to the database search problem in criminal proceedings , 2012, Investigative Genetics.

[3]  A P Dawid,et al.  Comment on Stockmarr's "Likelihood ratios for evaluating DNA evidence when the suspect is found through a database search". , 2001, Biometrics.

[4]  Anders Stockmarr.  The Choice of Hypotheses in the Evaluation of DNA Profile Evidence , 2000 .

[5]  A Stockmarr,et al.  Likelihood Ratios for Evaluating DNA Evidence When the Suspect is Found Through a Database Search , 1999, Biometrics.

[6]  W. M. Bolstad.  Introduction to Bayesian Statistics , 2004 .

[7]  Bruce Budowle,et al.  Developing criteria and data to determine best options for expanding the core CODIS loci , 2012, Investigative Genetics.

[8]  Sen. M.I.,et al.  Statistical Science in the Courtroom , 2001 .

[9]  F Taroni,et al.  The database search problem: a question of rational decision making. , 2012, Forensic science international.

[10]  F Taroni,et al.  Recent misconceptions about the 'database search problem': a probabilistic analysis using Bayesian networks. , 2011, Forensic science international.

[11]  B. Brinkmann,et al.  Allgemeine Empfehlungen der Spurenkommission zur statistischen Bewertung von DNA-Datenbank-Treffern , 2010, Rechtsmedizin.

[12]  J. Buckleton,et al.  Forensic DNA Evidence Interpretation , 2004 .

[13]  P Donnelly,et al.  DNA database searches and the legal consumption of scientific evidence. , 1997, Michigan law review.

[14]  Marjan Sjerps,et al.  Selection effects and database screening in forensic science. , 2009, Forensic science international.