Weight Of Evidence For Forensic Dna Profiles

DNA evidence is widely used in the modern justice system. Statistical methodology plays a key role in ensuring that this evidence is collected, interpreted, analysed and presented correctly. This book is a guide to assessing DNA evidence and presenting that evidence in a courtroom setting. A revised and updated edition of this practical guide to assessing DNA evidence and presenting that evidence in a courtroom setting. Throughout its history, DNA profiling has been controversial. As some controversies are resolved, ever more sensitive profiling techniques introduce new difficulties for the evaluation of evidential weight. Today, usable DNA profiles can be obtained from just a few cells, but such profiles may be affected by a range of stochastic effects. Faced with noisy evidence, courts and commentators tend to focus on the question of whether the technology is reliable, but this concept is too vague to be useful. What matters is whether the evaluation of evidential weight is meaningful to jurors and fair to defendants, allowing sufficiently for different sources of uncertainty. This book provides a thorough presentation of the basic theory of evidence evaluation for DNA profiles, and aims to equip forensic scientists with practical tools to allow them to present DNA evidence in court effectively. It will also be useful to lawyers who need to understand the meaning of statements of evidential weight for DNA evidence, and to challenge them. Requiring little expertise in either statistics or population genetics, Weight-of-Evidence for Forensic DNA Profiles: Links population genetics and statistics theory with practical issues surrounding the presentation of evidence in court; e.g. the prosecutor's fallacy, and the formulation and comparison of competing hypotheses. Shows how to calculate likelihood ratios from first principles, including a thorough interpretation of adjustments to allow for co-ancestry. Provides a self-contained introduction to population genetics relevant to DNA profiles and to the technology of short tandem repeat (STR, or microsatellite)-based profiling. Gives an overview of different evaluation software, and their underlying mathematical models, for low-template and degraded DNA profiles. Includes fully worked examples, as well as exercises with solutions. DNA evidence is widely used in the modern justice system. Statistical methodology plays a key role in ensuring that this evidence is collected, interpreted, analysed and presented correctly. This book is a guide to assessing DNA evidence and presenting that evidence in a courtroom setting. It offers practical guidance to forensic scientists with little dependence on mathematical ability, and provides the scientist with the understanding they require to apply the methods in their work. Since the publication of the first edition of this book in 2005 there have been many incremental changes, and one dramatic change which is the emergence of low template DNA (LTDNA) profiles. This second edition is edited and expanded to cover the basics of LTDNA technology. The author's own open-source R code likeLTD is described and used for worked examples in the book. Commercial and free software are also covered.

Offers guidance to forensic scientists with little dependence on mathematical ability. This book helps to assess DNA evidence and present that evidence in a courtroom setting. The introduction of DNA profiling into courtrooms during the late 1980s caused substantial controversy. Profiling techniques have advanced considerably since that time, and the power of DNA evidence is indisputable; but the importance of accurate evidence interpretation must not be underestimated. This book provides a thorough presentation of weight-of-evidence for DNA profiling, and aims to help both the lawyer and the forensic scientist charged with presenting DNA evidence in court. Links up population genetics and statistics theory with the reality of issues surrounding the presentation of evidence in court; e.g. the prosecutor’s fallacy, and the introduction of Bayesian methods in the courtroom. Shows how to calculate likelihood ratios from first principles, including a thorough interpretation of the θ adjustments to allow for co-ancestry. Provides a self-contained introduction to population genetics relevant to DNA profiles. Provides an introduction to the technology of short random repeat (STR, or microsatellite) based profiling, and a brief introduction to SNP profiles. Provides a comparison with alternative methods for evaluating weight-of-evidence, e.g. uniqueness, exclusion probabilities, and hypothesis training. Fully worked examples given throughout the book, as well as exercises with solutions. Weight-of-evidence for forensic DNA profiles is aimed at forensic scientists presenting evidence in court as well as all students of evidence interpretation. Little background is necessary in either statistics or population genetics; statisticians however will find fascinating applications of important statistical concepts . This book is also suitable for judges and lawyers seeking to attain a thorough understanding of weight-of-evidence theory, and those interested in the application of these principles to the legal field and their presentation in the courtroom. Assessing Weight-of-Evidence for DNA Profiles is an excellent introductory text to the use of statistical analysis for assessing DNA evidence. It offers practical guidance to forensic scientists with little dependence on mathematical ability as the book includes background information on statistics – including likelihood ratios – population genetics, and courtroom issues. The author, who is highly experienced in this field, has illustrated the book throughout with his own experiences as well as providing a theoretical underpinning to the subject. It is an ideal choice for forensic scientists and lawyers, as well as statisticians and population geneticists with an interest in forensic science and DNA.