1,721,158 research outputs found
Decision analysis in forensic science
No full textForensic scientists are routinely faced with the problems of making decisions under circumstances of uncertainty (i.e., to perform or not perform a test). A decision making model in forensic science is proposed, illustrated with an example from the field of forensic genetics. The approach incorporates available evidence and associated uncertainties with the assessment of utilities (or desirability of the consequences). The paper examines a general example for which identification will be made of the decision maker, the possible actions, the uncertain states of nature, the possible source of evidence and the kind of utility assessments required. It is argued that a formal approach can help to clarify the decision process and give a coherent means of combining elements to reach a decision
Forensic inference and statistics for the evaluation and interpretation of evidence
No full textEvidence in a criminal investigation and trial should be evaluated and interpreted in the best manner possible. An excellent, and widely supported, approach to evaluation is one - by nature probabilistic - based on the likelihood ratio, the ratio of the probability of the evidence if a certain (set of) proposition(s) (e.g., prosecution) is assumed true to the probability of the evidence if a contrasting (set of) proposition(s) (e.g., defence) is assumed true. The justification for this approach is given together with a note of the benefits arising from the use of this ratio. There is a discussion about the meaning of probability as a measure of belief, the use of numerical assignments and verbal expressions and the use of the likelihood ratio for interpretation. It is explained how beliefs can be updated in the light of new evidence, how multiple pieces of evidence may be evaluated with the use of graphical structures and how uncertainty associated with the numerical evaluation, which is probabilistic, may be handled. A procedure for judgement of the quality of the mathematical formulae used in the calculation of the likelihood ratio is outlined. A conclusion gives three important principles that an expert, and a forensic scientist in particular, should follow when trying to understand the importance of evidence
The Role of the Bayes Factor in the Evaluation of Evidence
Full text linkThe use of the Bayes factor as a metric for the assessment of the probative value of forensic scientific evidence is largely supported by recommended standards in different disciplines. The application of Bayesian networks enables the consideration of problems of increasing complexity. The lack of a widespread consensus concerning key aspects of evidence evaluation and interpretation, such as the adequacy of a probabilistic framework for handling uncertainty or the method by which conclusions regarding how the strength of the evidence should be reported to a court, has meant the role of the Bayes factor in the administration of criminal justice has come under increasing challenge in recent years. We review the many advantages the Bayes factor has as an approach to the evaluation and interpretation of evidence
Bayes Factor and the Value of Evidence
No full textProbability is the reference framework for scientific reasoning under uncertainty. Bayes’ theorem, a consequence of probability theory and related concepts, provides a way to formalize the assessment of the value of the evidence with respect to propositions of judicial interest
Statistics and the evaluation of evidence for forensic scientists
No full textThe third edition of Statistics and the Evaluation of Evidence for Forensic Scientists is fully updated to provide the latest research and developments in the use of statistical techniques to evaluate and interpret evidence. Courts are increasingly aware of the importance of proper evidence assessment when there is an element of uncertainty. Because of the increasing availability of data, the role of statistical and probabilistic reasoning is gaining a higher profile in criminal cases. That’s why lawyers, forensic scientists, graduate students, and researchers will find this book an essential resource, one which explores how forensic evidence can be evaluated and interpreted statistically. It’s written as an accessible source of information for all those with an interest in the evaluation and interpretation of forensic scientific evidence.
Discusses the entire chain of reasoning–from evidence pre-assessment to court presentation;
Includes material for the understanding of evidence interpretation for single and multiple trace evidence;
Provides real examples and data for improved understanding.
Since the first edition of this book was published in 1995, this respected series has remained a leading resource in the statistical evaluation of forensic evidence. It shares knowledge from authors in the fields of statistics and forensic science who are international experts in the area of evidence evaluation and interpretation. This book helps people to deal with uncertainty related to scientific evidence and propositions. It introduces a method of reasoning that shows how to update beliefs coherently and to act rationally. In this edition, readers can find new information on the topics of elicitation, subjective probabilities, decision analysis, and cognitive bias, all discussed in a Bayesian framework
Analysis of sampling issues using Bayesian networks
No full textThis paper addresses the implementation of Bayesian sampling methodology in a graphical probability environment, i.e. Bayesian networks (BNs). An architecture of BNs which is able to be used for sampling from small and large consignments is outlined in detail. Through direct interaction with their users, the proposed models provide a framework that is capable of dealing with several distinct sampling issues, such as (i) the calculation of posterior probability distributions for the proportion of ‘positives’ (i.e. discrete units with a characteristic of interest) in a consignment as well as for the number of positives among a consignment’s uninspected items, (ii) case preassessment and (iii) likelihood-ratio evaluation. A discussion is included on features of the proposed models that allow one to account for further complications such as competing prior beliefs about the proportion of positives in a consignment and potentially misclassified data (e.g. positive testing results obtained from units that are actually negative)
Data analysis in forensic science: A Bayesian decision perspective.
No full textThe use of formal statistical methods to analyse quantitative data in forensic science has increased considerably over the last few years. Students, researchers and practitioners in forensic science regularly ask questions concerning the relative merits of differing approaches, in particular the frequentist and Bayesian approaches, to statistical inference in the forensic context. The ideas of the Bayesian approach in forensic science are now being extended to include decision theory and the associated concept of utility.
Data Analysis in Forensic Science: A Bayesian Decision Perspective sets forth procedures for data analysis that rely on the decision-theoretic approach to inference. Emphasis is made on foundational philosophical tenets as well as the implications of the decision-theoretic approach in practice. This book discusses a range of statistical decision-theoretic methods that are useful in the analysis of forensic scientific data. Forensic scientific examples include point estimation, the comparison of means and proportions in populations, the choice of sample size and the classification of items of evidence of unknown origin into predefined populations.
Key Features:
- Comprehensive coverage of the analysis of forensic data from a Bayesian perspective, featuring numerous real-world examples and applications.
- Explanation and definition of key concepts and methods from historical, philosophical, and theoretical points of view.
- An incremental approach for consideration of examples inspired and motivated by issues that may arise in routine forensic practice.
- Consideration of the arguments and methods, including those of decision theory, used at each stage of the analyses.
- Inclusion of code written in R to offer an opportunity for enhanced exploration of the ideas.
- The use of graphical models (e.g. Bayesian networks) to illustrate selected applications of Bayesian methodology
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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