An Improved Version of a Tool Mark Comparison Algorithm

Chumbley et al. (2010) described a statistically based algorithm for comparing pairs of tool marks. They presented empirical evidence that the algorithm produces well‐separated similarity score values for “matching” and “non‐matching” pairs of tool marks. However, the algorithm has two substantial weaknesses. First, it is “uncalibrated” in the sense that error rates can be determined only through empirical investigation. Second, it relies on a randomized test and can lead to different similarity scores when the algorithm is repeatedly applied to the same pair of tool marks. We present an improved version of the procedure, which eliminates the randomized scores and yields more consistent and predictable error rate control. This is accomplished by replacement of a random sampling step from the original algorithm with a deterministic process. We demonstrate the improved algorithm and compare its performance to the original by applying to known “matching” and “non‐matching” pairs of tool marks.     

Attrition in the RAND Health Insurance Experiment: a response to Nyman

In a prior article in this journal, John Nyman argues that the effect on health care use and spending found in the RAND Health Insurance Experiment is an artifact of greater voluntary attrition in the cost-sharing plans relative to the free care plan. Specifically, he speculates that those in the cost-sharing plans, when faced with a hospitalization, withdrew. His argument is implausible because (1) families facing a hospitalization would be worse off financially by withdrawing; (2) a large number of observational studies find a similar effect of cost sharing on use; (3) those who left did not differ in their utilization prior to leaving; (4) if there had been no attrition and cost sharing did not reduce hospitalization rates, each adult in each family that withdrew would have had to have been hospitalized once each year for the duration of time they would otherwise have been in the experiment, an implausibly high rate; (5) there are benign explanations for the higher attrition in the cost-sharing plans. Finally, we obtained follow-up health-status data on the great majority of those who left prematurely. We found the health-status findings were insensitive to the inclusion of the attrition cases.     

Validation of Tool Mark Comparisons Obtained Using a Quantitative,Comparative, Statistical Algorithm

Abstract: A statistical analysis and computational algorithm for comparing pairs of tool marks via profilometry data is described. Empirical validation of the method is established through experiments based on tool marks made at selected fixed angles from 50 sequentially manufactured screwdriver tips. Results obtained from three different comparison scenarios are presented and are in agreement with experiential knowledge possessed by practicing examiners. Further comparisons between scores produced by the algorithm and visual assessments of the same tool mark pairs by professional tool mark examiners in a blind study in general show good agreement between the algorithm and human experts. In specific instances where the algorithm had difficulty in assessing a particular comparison pair, results obtained during the collaborative study with professional examiners suggest ways in which algorithm performance may be improved. It is concluded that the addition of contextual information when inputting data into the algorithm should result in better performance.     

Did the “Road to the White House Run Through” Letterman? Chris Christie,Letterman, and Other-Disparaging Versus Self-Deprecating Humor

In this article we present the results of an experiment designed to disentangle the effects late-night talk show viewership have on presidential candidate evaluations. Respondents in one condition viewed a short video clip of David Letterman humorously disparaging New Jersey Governor Chris Christie, thought by many at the time to be considering a run for the presidency in 2016. Those in a second condition saw a short clip of Christie engaging in self-deprecating humor while appearing as a guest on Letterman's program. Compared with respondents in a control condition, those in the other-disparaging humor condition had lower evaluations of Christie and reported a lower likelihood of voting for him in 2016, while those in the self-deprecating humor condition had higher evaluations of him and expressed a greater likelihood of voting for him. The research has practical implications for modern campaigns and also serves to clarify some of the seemingly contradictory findings of earlier political humor effects research.     

Exploring the Link Between Being Bullied and Adolescent Substance Use

Although research suggests that bullied adolescents may respond to victimization with substance use, much of this prior work has been cross-sectional. Using longitudinal data from a community-based sample, we examine the impact of early bullying victimization on the initiation of substance use in adolescence after considering the potential influence of selection effects using propensity score matching. After matching, there were moderate differences between victims of bullying and control students for cigarette smoking and alcohol use, which was limited to those exposed to higher levels of bullying. Being bullied in childhood appears to have only minor effects on the onset of adolescent substance use in this sample.     

European Monarchies: Guardians of Democracy?

How is it possible to account for the continuing presence of monarchy in advanced social democracies? Much traditional political science assumes teleologically that monarchies inevitably transform into republics as a higher form of governance. This comparative study of the eight main European monarchies maintains otherwise: monarchy is perfectly compatible with democracy, and can help strengthen citizens’ loyalty to the system of government. Provided it delivers a politically impartial head of state, monarchy can endure indefinitely with government and popular support. In practice, the countries studied are de facto republics, but with hereditary heads of state who occupy social roles beyond the reach of quotidian politics. Monarchy’s principal danger is not republicanism, but the pressures of conflicting expectations about what is required of royal families, and the relentless intrusions of modern media in an age when royalty and celebrity are in danger of being conflated. Responses to Covid-19 show how monarchs can speak to and for their nations in ways no partisan politician can.     

Three-Dimensional Analysis of Cartridge Case Double-Casts

Due to the shot-to-shot variability in tool mark reproduction on fired cartridge cases, a method of replication is needed for the creation of training and testing sets. Double-casting is one method that has been used for this application, but the accuracy and variability of this method needs to be characterized. Three firearms were used to fire 25 cartridges each to create the master cartridge cases. The double-casting method consists of creating a silicone mold of the master cartridge case. A plastic resin mix is then poured into the mold to create the double-cast reproduction. Fifteen double-casts of each of the 75 fired cartridge cases were created across different silicone molds to analyze within- and between-mold variability. The master cartridge cases and double-casts were scanned with a confocal microscope (Sensofar® S neox) to create three-dimensional representations of the surfaces. Two similarity metrics were used for the objective comparison of the double-casts to their master cartridge cases: the areal correlation coefficient (ACCF_MAX) and the number of congruent matching cells (CMC). The ACCF_MAX and CMC data, along with visual examinations, showed that the double-casting method produces accurate reproductions. Within-mold variability was found to be minimal, and between-mold variability was low. These results illustrate that double-casting can be applied for training and testing purposes.     

Policy Matters

TOP-US O-GE SIT, USE LUN LEVA. HEL DEKA O-VIV-US GAN DA KOVI. IN UKI-US HUZI, ERS-MANI REVA. UD ZITA DA OGL ETO UVO BOVI. TATAT-US SEMI OF AVE SOMA

Above the dirty city, a white moon rises. Frost covers the dead garden and flowers. In their houses, peasants dream. I sit and watch these gray boxes. Hidden seeds of the future are sleeping.

Rick Harrison (translation of the original from the artificial language UNI)

The paradox of race in America is that our common destiny is more pronounced and imperiled precisely when our divisions are deeper?…?There is no escape from our interracial interdependence, yet our enforced racial hierarchy dooms us as a nation—the unmaking of any democratic order.

Cornel West (2001 West, C. 2001. Race Matters., , 2nd, New York: Vintage Books.  [Google Scholar], 9)

Dear George Bush: I remember racial profiling, and how all of these other constitutional violations have been used for centuries, especially against the African-American community, and that minority citizens and immigrants have been subject to some of the grossest infringements of civil liberties—the two words that uphold the very power of democracy—for a very long time.

Kristin Prevallet     

The use of error rates to predict and characterize the efficacy of presumptive field tests

From a forensic perspective, a presumptive test, one which indicates the presence or absence of a certain target material such as blood, is an invaluable tool. Among these tests, there are different specificities, sensitivities, and shelf lives. The accuracy of a test is an algebraic combination of the specificity and sensitivity of the test. Each test has limitations as given by its false positive and false negative rates. The aim of this study was to illustrate how the false positive and false negative rates are to be properly determined using a simulation study for the phenolphthalein test. New presumptive tests must be properly evaluated/validated through testing of commonly encountered household items and other potentially probative items usually found at crime scenes, however, the makeup of test sets must appropriately capture all error rates. In order to correctly use these results when the test is applied to an unknown sample recovered at a crime scene, the error rates cannot be applied directly to estimate whether or not the sample is actually the analyte of interest. In a validation study, the forensic scientist calculates the false positive rate as the p(Positive Reaction|Blood), whereas at the scene, the crime scene investigator wishes to determine the p(Blood|Positive Reaction). All crime scene investigators need to ensure that the conditional is not transposed when interpreting such results. Furthermore, this work provides a model for the assessment of a multiple test diagnostic system intended for investigators.