Reference ballistic imaging database performance

Ballistic imaging databases allow law enforcement to link recovered cartridge cases to other crime scenes and to firearms. The success of these databases has led many to propose that all firearms in circulation be entered into a reference ballistic image database (RBID). To assess the performance of an RBID, we fired 4200 cartridge cases from 600 9mm Para Sig Sauer model P226 series pistols. Each pistol fired two Remington cartridges, one of which was imaged in the RBID, and five additional cartridges, consisting of Federal, Speer, Winchester, Wolf, and CCI brands. Randomly selected samples from the second series of Remington cartridge cases and from the five additional brands were then correlated against the RBID. Of the 32 cartridges of the same make correlated against the RBID, 72% ranked in the top 10 positions. Likewise, of the 160 cartridges of the five different brands correlated against the database, 21% ranked in the top 10 positions. Generally, the ranking position increased as the size of the RBID increased. We obtained similar results when we expanded the RBID to include firearms with the same class characteristics for breech face marks, firing pin impressions, and extractor marks. The results of our six queries against the RBID indicate that a reference ballistics image database of new guns is currently fraught with too many difficulties to be an effective and efficient law enforcement tool.     

‘Wasn't me!’ A field study of the relationship between deceptive motivations and psychopathic traits in young offenders

Purpose. Evaluating truthfulness is an integral part of any forensic assessment. Unfortunately, the motives underlying the use of deceptive strategies by offenders and how these may be mediated by personality are not well established, particularly in adolescent samples. Accordingly, the aim of the present study was to identify different deception‐related motivations in a sample of juvenile offenders, with special emphasis placed on the relationship between these motivations and psychopathic traits. Methods. Archived file and videotaped information for 60 Canadian federal juvenile offenders were reviewed in order to identify real‐life (spontaneous) patterns of deceptive motivations. Results. It was found that there were significant differences between the low, medium, and high groups across psychopathic traits for the motivations of (1) lies to obtain a reward; (2) to heighten self‐presentation; and (3) for duping delight. Conclusions. Not only were juvenile offenders found to lie for a variety of reasons, but also psychopathy was found to mediate the specific motivational patterns leading to offender perpetrated deception. The relevance of these findings to the assessment of truthfulness in offender populations is discussed.     

Les enjeux de l'évaluation de la performance : Dépasser les mythes

Since the 1990s, most Western countries have equipped themselves with frameworks and tools to measure health organizations and systems' performance. Paradoxically, several theoretical, methodological and usage issues remain unresolved. Conceptually, the notion of performance is vague and not well rooted in theory. From a methodological perspective, we are faced with numerous measures that don't always meet reliability, validity and usefulness criteria and don't help to grasp the complexity of the concept. Finally, the assessment results are not fully used to continuously improve performance. This article focuses on analyzing these issues by deconstructing the myths that slow down the development of better‐suited frameworks to meet decision‐makers' needs. It also proposes innovations based on the global and integrated assessment model of health systems.     

Reference ballistic imaging database performance

Ballistic imaging databases allow law enforcement to link recovered cartridge cases to other crime scenes and to firearms. The success of these databases has led many to propose that all firearms in circulation be entered into a reference ballistic image database (RBID). To assess the performance of an RBID, we fired 4200 cartridge cases from 600 9 mm Para Sig Sauer model P226 series pistols. Each pistol fired two Remington cartridges, one of which was imaged in the RBID, and five additional cartridges, consisting of Federal, Speer, Winchester, Wolf, and CCI brands. Randomly selected samples from the second series of Remington cartridge cases and from the five additional brands were then correlated against the RBID. Of the 32 cartridges of the same make correlated against the RBID, 72% ranked in the top 10 positions. Likewise, of the 160 cartridges of the five different brands correlated against the database, 21% ranked in the top 10 positions. Generally, the ranking position increased as the size of the RBID increased. We obtained similar results when we expanded the RBID to include firearms with the same class characteristics for breech face marks, firing pin impressions, and extractor marks. The results of our six queries against the RBID indicate that a reference ballistics image database of new guns is currently fraught with too many difficulties to be an effective and efficient law enforcement tool.     

Gender Determination of Adult Individuals by Three‐Dimensional Modeling of Canines

Gender determination is a fundamental issue in forensic anthropology. Many techniques based on bone and dental remains have been proposed. It is not always possible to implement the techniques using bones, but teeth are often perfectly preserved. It has been demonstrated that the canine has the greatest sexual dimorphism, and the aim of this work was to provide an easy and accurate dental technique for determining the gender in the absence of other skeletal elements. The sample was composed of 210 CT scans with four healthy canines. The 840 canines were modeled using MIMICS^® 10.01 software. The total volume of each tooth was determined. Seven mathematical models were determined by binary logistic regressions and ranked in order of relative performance. The seven proposed predictive models thus performed (0.910 ≤ AUC ≤ 0.938), with overall rates of correct predictions between 82.38 and 85.24%. The 4‐canine model is the most powerful for predicting the gender.