The Burglary Boost: A Note on Detecting Contagion Using the Knox Test

Objectives

A large body of literature in quantitative criminology finds that the spatio-temporal clustering of burglary is greater than one would expect from chance alone. This suggests that such crimes may exhibit a “boost” effect, wherein each burglary increases the risk to nearby locations for a short period. In this study, we demonstrate that standard tests for spatio-temporal dependence have difficulty distinguishing between clustering caused by contagion and that caused by changing relative risks. Therefore, any estimates of the boost effect drawn from these tests alone will be upwardly biased.

Methods

We construct an agent-based model to generate simulated burglary data, and explore whether the Knox test can reliably distinguish between contagion (one burglary increases the likelihood of another burglary nearby) and changes in risk (one area gets safer while another gets more dangerous). Incorporating insights from this exercise, we analyze a decade of data on burglary events from Washington, DC.

Results

We find that (1) absent contagion, exogenous changes in relative risk can be sufficient to produce statistically significant Knox ratios, (2) if risk is changing over time, estimated Knox ratios are sensitive to one’s choice of time window, and (3) Knox ratios estimated from Washington, DC burglary data are sensitive to one’s choice of time window, suggesting that long-run changes in relative risk are, in part, driving empirical estimates of burglary’s boost effect.

Conclusions

Researchers testing for contagion in empirical time series should take precautions to distinguish true contagion from exogenous changes in relative risks. Adjusting the time window of analysis is a useful robustness check, and future studies should be supplemented with new approaches like agent-based modeling or spatial econometric methods.

     

The Role of Site Variance in the American Judicature Society Field Study Comparing Simultaneous and Sequential Lineups

Objectives

Police departments often use photo lineups for eyewitness identification purposes. A widely adopted lineup reform designed to reduce eyewitness misidentifications involves switching from the standard simultaneous photo presentation format to a sequential format. These two lineup procedures were recently tested in the American Judicature Society (AJS) field study, which was conducted in four different police jurisdictions. The results from two phases of that investigation reached opposite conclusions as to which lineup procedure is superior, and the purpose of our current investigation was to elucidate the role of site variance in shaping those contrasting conclusions.

Methods

In previous analyses, the field study data were either (1) aggregated across all four study sites or (2) drawn from only one study site (Austin, Texas). Here, we analyze the data separately for the Austin study site, where 69 % of the eyewitnesses were tested, and the other three study sites combined, where 31 % of the eyewitnesses were tested.

Results

The results indicate significant site variance between the Austin and non-Austin study sites. In addition, the results suggest that aggregating the data across sites played a determinative role in creating the apparent disagreement about which lineup procedure is diagnostically superior.

Conclusions

Once large differences across the AJS study sites are taken into consideration, there is no longer any disagreement about which lineup procedure is superior. The simultaneous procedure is diagnostically superior to the sequential procedure, but the sequential procedure sometimes induces more conservative responding (a result that can and often does masquerade as diagnostic superiority).

     

‘Prefer not to say’: diversity and diversity reporting at the bar of England & Wales

The Bar of England & Wales, like the wider legal profession, does not reflect the society it serves. The current data published by the Bar Standards Board (BSB) suggests a profile in relation to gender and ethnicity that gives serious cause for concern. As regards additional diversity characteristics, the BSB (and others) have accepted that the existing datasets are not wholly reliable because of poor response rates to associated diversity questionnaires. In 2011, the Legal Services Board (LSB) introduced mandatory guidance that obliged its daughter regulators to put into place rules that relate to diversity monitoring and reporting across the legal profession. This paper is concerned with how the BSB has operationalised that statutory guidance in respect of the Bar. Drawing on data gathered from the websites of 160 chambers, I show significant non-compliance with the reporting rule, and question both how the BSB itself reports on diversity data and the drafting of the reporting rule. I ask whether non-compliance is partly a function of the complexity seen in how the BSB has made operational the LSB’s reporting requirements. My data also suggests that the BSB should target its enforcement and educational approaches to the reporting rule to small and medium sized chambers.     

Second Face of Security Strategies: Anglo-German and Anglo-Japanese Trade Concessions During the 1930s

Great powers can pursue deliberate Trojan horse policies to transform rising and threatening states into followers and supporters rather than challengers by altering their domestic political and economic institutions. I contend that a great power can use trade concessions, rather than punishment, to enable a favorable foreign policy coalition in a target country. The intent is to strengthen the political power of state and societal elites who have a stake in deepening international ties, while opponents of such policies will be weakened politically and economically. The societal winners will then apply pressure on the government to support their preferred outward-oriented grand strategy. I term this process the second face of security since it entails a less direct and more nuanced method of creating security. I examine Britain's commercial policies toward Germany and Japan during the 1930s to better understand second-face strategies. I argue that the intent of Britain's industrial and commercial policy was to strengthen conservative business, government officials, and economic circles in banking, light industry, and finished goods, and even heavy industry in order to steer Berlin and Tokyo away from rearmament, extreme autarky, and war.     

THE CASCADING EFFECTS OF ADOLESCENT GANG INVOLVEMENT ACROSS THE LIFE COURSE*

The short‐run deleterious effects of gang involvement during adolescence have been well researched. However, surprisingly little empirical attention has been devoted to understanding how gang involvement in adolescence influences life chances and criminal behavior in adulthood. Drawing on the life‐course perspective, this study argues that gang involvement will lead to precocious transitions that, in turn, will have adverse consequences on the fulfillment of adulthood roles and statuses in the economic and family spheres. Moreover, problems fulfilling these conventional roles are hypothesized then to lead to sustained involvement in criminal behavior in adulthood. Using data from a sample of males from the Rochester Youth Development Study, results from structural equation models support the indirect link between gang membership and noncriminal and criminal outcomes in adulthood. Specifically, gang involvement leads to an increase in the number of precocious transitions experienced that result in both economic hardship and family problems in adulthood. These failures in the economic and family realms, in turn, contribute to involvement in street crime and/or arrest in adulthood. Implications for the criminal desistance process are discussed.