A general approach to Bayesian networks for the interpretation of evidence

Bayesian networks (BNs) are mathematically and statistically rigorous techniques for handling uncertainty. The field of forensic science has recently attributed increased attention to the many advantages of this graphical method for assisting the evaluation of scientific evidence. However, the majority of contributions that relate to this topic restrict themselves to the presentation of already "constructed" BNs, and often, only a few explanations are given as to how one obtains a specific BN structure for a given problem. Based on several examples, the present paper will therefore attempt to explain in more detail some guiding considerations that might be helpful for the elicitation of appropriate structures for BNs.     

Parliamentary Question Times: How Legislative Accountability Mechanisms Affect Mass Political Engagement

Over time, people have been losing interest in politics. Some believe this to be one of the largest challenges facing democracy today. What causes some citizens to be more engaged than others? This paper argues that national-level political institutions are important in shaping the tone of political debate between election campaigns. Some countries have regular, accessible debates between political leaders; in others the debate is rarer and harder to follow. Parliamentary question time (QT) is a prominent forum for regular elite-level debate, and QTs featuring open, accessible debate should help induce citizens to engage with politics by providing them with an information-laden political spectacle. The data show that these open QTs are associated with higher levels of political knowledge, partisanship, and turnout.     

Objective Evaluation of Subclass Characteristics on Breech Face Marks

Subclass characteristics can be found on the breech face marks left on spent cartridge cases. Even if they are assumed to be rare and their reported number is small, they can potentially lead to false associations. Subclass characteristics have been studied empirically allowing examiners to recognize them and to understand in which conditions they are produced. Until now, however, their influence on the identification process has not been studied from a probabilistic point of view. In this study, we aim at measuring the effect of these features on the strength of association derived from examinations involving subclass characteristics. The study takes advantage of a 3D automatic comparison system allowing the calculation of likelihood ratios (LRs). The similarities between cartridge case specimens fired by thirteen S&W .40S&W Sigma pistols are quantified, and their respective LRs are computed. The results show that the influence of subclass characteristics on the LRs is limited, even when these features are prevalent among the potential sources considered in a case. We show that the proportion of firearms sharing subclass characteristics should be larger than 40% of the pool of potential firearms for the effect to be significant.     

A two-level model for evidence evaluation

A random effects model using two levels of hierarchical nesting has been applied to the calculation of a likelihood ratio as a solution to the problem of comparison between two sets of replicated multivariate continuous observations where it is unknown whether the sets of measurements shared a common origin. Replicate measurements from a population of such measurements allow the calculation of both within-group and between-group variances/covariances. The within-group distribution has been modelled assuming a Normal distribution, and the between-group distribution has been modelled using a kernel density estimation procedure. A graphical method of estimating the dependency structure among the variables has been used to reduce this highly multivariate problem to several problems of lower dimension. The approach was tested using a database comprising measurements of eight major elements from each of four fragments from each of 200 glass objects and found to perform well compared with previous approaches, achieving a 15.2% false-positive rate, and a 5.5% false-negative rate. The modelling was then applied to two examples of casework in which glass found at the scene of the criminal activity has been compared with that found in association with a suspect.     

Driving racial profiling research forward: Learning lessons from sentencing research

Discretion is an integral component of the criminal justice system and is exercised by both police and the judiciary. Based on the extant research, evidence of racial/ethnic disparities within the context of traffic stops and sentencing decisions has been documented. Due to its long history of inquiry, sentencing research has developed a more thorough understanding of disparity and its correlates. This article contends that racial profiling research could expedite its development by learning from the history of sentencing research. Specifically, the extant research on sentencing decisions has demonstrated the value and utility of theory and methods as pillars of knowledge development. Therefore, progress in racial profiling research is most likely accomplished by employing similar theoretical frameworks and appropriate quantitative and qualitative approaches.     

Restructuring Local Government in Hampshire: A Case of Mistaken Community Identity?

This article examines the impact of the idea of community identity upon the Local Government Review in England. It considers the extent to which the notion of community identity was built into the Local Government Review nationally and, moreover, locally in Hampshire, and the extent to which it shaped the outcomes of the Local Government Review. Three conceptions of community identity are examined - affective, effective and deliberative community identity - and their interplay assessed in shaping the process of restructuring local government. The article argues that the issue of community identity figured prominently in the early stages of the Local Government Review, but faded away as it got caught up with the political machinations of central government, local authorities and political parties.     

Crime in the Australian fishing industry: Key issues

This research suggests that opportunities exist for a wide range of criminal activity in Australia’s commercial fishing sector.Organised crime is attracted to the fishing industry because it is percieved as being a low-risk, high-gain endeavour involving high-value, low-volume product with a lucrative overseas market. Jurisdictions are trying to implement strategies to inhabit these activities in valuable, but diminishing sectors, such as abalone. These efforts have to extend across all attractive seafood products, for example, seahorse and shark fin. To do so sucessfully will require a range of operational, legeslative and educational strategies, implemented uniformly and (where possible) simultaneously across jurisdictions and bolstered by international support and cooperation. This will inhibit the likehood of displacement and will result in a greater ability by fisheries enforcement agencies to focus their resources. Disclaimer: This research paper does not necessarily reflect the policy position of the Australian Government. The Australian Institute of Criminology (the Institute) and the Commonwealth of Australia accept no responsibility for the content, accuracy or completeness of [this] material... This material is made available on the understanding that neither the Institute nor the Commonwealth is thereby engaged in rendering professional or expert advice. The material may include views of third parties and does not necessarily reflect the views of the Institute or the Commonwealth.