Predictive Crime Mapping: Arbitrary Grids or Street Networks?

Objectives

Decades of empirical research demonstrate that crime is concentrated at a range of spatial scales, including street segments. Further, the degree of clustering at particular geographic units remains noticeably stable and consistent; a finding that Weisburd (Criminology 53:133–157, 2015) has recently termed the ‘law of crime concentration at places’. Such findings suggest that the future locations of crime should—to some extent at least—be predictable. To date, methods of forecasting where crime is most likely to next occur have focused either on area-level or grid-based predictions. No studies of which we are aware have developed and tested the accuracy of methods for predicting the future risk of crime at the street segment level. This is surprising given that it is at this level of place that many crimes are committed and policing resources are deployed.

Methods

Using data for property crimes for a large UK metropolitan police force area, we introduce and calibrate a network-based version of prospective crime mapping [e.g. Bowers et al. (Br J Criminol 44:641–658, 2004)], and compare its performance against grid-based alternatives. We also examine how measures of predictive accuracy can be translated to the network context, and show how differences in performance between the two cases can be quantified and tested.

Results

Findings demonstrate that the calibrated network-based model substantially outperforms a grid-based alternative in terms of predictive accuracy, with, for example, approximately 20 % more crime identified at a coverage level of 5 %. The improvement in accuracy is highly statistically significant at all coverage levels tested (from 1 to 10 %).

Conclusions

This study suggests that, for property crime at least, network-based methods of crime forecasting are likely to outperform grid-based alternatives, and hence should be used in operational policing. More sophisticated variations of the model tested are possible and should be developed and tested in future research.

     

Isolating Adult Psychological Correlates of Witnessing Parental Violence: Findings from a Predominantly Latina Sample

This study examined the relationship between childhood exposure to parental violence and adult psychological functioning in a sample of predominantly Mexican American participants. Questionnaires assessing childhood maltreatment, family environment, and current psychological symptomatology were completed by 142 female undergraduates. Findings revealed that witnessing parental violence in childhood was associated with depressive symptoms, low self-esteem, and trauma symptoms in adulthood, even after controlling for child physical and sexual abuse. However, in subsequent analyses, also controlling for levels of nonphysical family conflict, previous associations between exposure to parental violence and adult symptomatology were reduced, such that trauma-related symptoms remained the sole outcome still predicted by a history of witnessing parental violence. Implications of these findings, issues related to the use of statistical control procedures in abuse effects research, and directions for future investigation are discussed.     

Secured Financing of Intellectual Property Assets and the Reform of English Personal Property Security Law

The past three decades have seen a decline in traditional industriesin the United Kingdom and there has been a relative declinein the value of physical assets to the UK economy. At the sametime, the value of intangible assets seen in intellectual propertyrights have increased considerably. As such, IP rights representimportant assets for companies and often comprise the foundationfor market dominance and continued profitability. There is astructural uncertainty in the law relating to the use of IPas collateral for the purpose of raising debt finance and thismay impact upon the survival of firms with high ratios of intangibleto tangible assets. This article considers the proper goalsfor an effective credit and security regime in IP. It examinesthe significance of the availability of collateral to the lendingdecision and also considers whether the reluctance to maximisethe use of IP as security reflects inherent difficulties whicharise out of the nature of IP as economic assets. This has implicationsfor the reform of English personal property security law andthe development of bright line priority rules associated withArticle 9 of the US Uniform Commercial Code which is often citedas a model for reform of English law.     

Investigation of cardiac troponins in postmortem subjects: comparing antemortem and postmortem levels

The limitations of autopsy in the diagnosis of death due to ischemic heart disease are well known. In the living, a simple reliable biochemical assay for cardiac troponins is used in the diagnosis of acute myocardial ischemia. Several studies have investigated the use of biochemical assays for cardiac troponins in postmortem subjects as a means to distinguish between a cardiac and anoncardiac cause of death. All of these studies, however, rely upon assigning subjects to "cardiac" or "noncardiac" death on the basis of a postmortem examination. As postmortem examination does not always accurately distinguish between these two groups, this approach is intrinsically flawed.Our study compares antemortem and postmortem cardiac troponin levels in five subjects. The antemortem samples were retrieved from the hospital biochemistry laboratory after each subject's death. The postmortem samples for each subject were taken from different sites and at different times during the early postmortem period.Erratic results bearing little or no relation to the antemortem cardiac troponin level were obtained for all subjects. Four of the five subjects had raised antemortem troponin levels, although only one had a cardiac cause of death.From this, we conclude that postmortem blood is not a suitable substrate for standard biochemical assays of cardiac troponins, which are designed for use on serum taken from living patients. In addition, the results of our study support the view that elevated cardiac troponins are a marker of serious morbidity and are not specific for cardiac injury as the primary cause of morbidity or mortality.     

An overview of the National Survey of SSI Children and Families and related products

The National Survey of SSI Children and Families (NSCF) is the first nationally representative survey since 1978 of noninstitutionalized children and young adults who currently receive or formerly received Supplemental Security Income (SSI). Over 8,500 interviews were completed between July 2001 and June 2002. The primary objective of the NSCF is to provide data to support research and policy evaluation on the current cross section of children (ages 0 to 17) and young adults (ages 18 to 23) receiving SSI. Following that objective, the survey was designed to answer questions such as those presented below. What are the general characteristics of children and young adults receiving SSI and their families? What are the patterns of access to and utilization of health care among children and young adults receiving SSI? What services are utilized by children and young adults receiving SSI? What are the unmet health care and service needs of children and young adults receiving SSI? What costs are associated with caring for a disabled child? What is the impact on the family of having a disabled child? What is the status of young adults with disabilities as they make the transition to adulthood? How well are they prepared for that transition? In addition, the NSCF questionnaire and sample were designed to be comprehensive enough and large enough to address numerous additional policy issues as they emerge. The NSCF fills a gap in the data available to policy analysts by addressing a wide range of topics that cannot be addressed with SSI administrative data and by providing a large sample in contrast to major national survey databases that cover this target population fairly sparsely. A companion article to this overview describes general characteristics of SSI beneficiary children and their families (see Rupp and others 2005/2006, pages 21-48 of this issue). Other topics being examined include disability-related expenditures for SSI children and young adults and labor force participation of the parents of SSI children. The NSCF data files are accompanied by a detailed User's Manual, which includes a detailed codebook and information about the NSCF sample design, questionnaire design and content, data collection procedures, variable construction, editing, and variance estimation procedures. In order to facilitate research, the Social Security Administration published the NSCF Public-Use File and survey documentation on its Web site. These products are available at http://www.socialsecurity.gov/disabilityresearch/nscf.htm. The NSCF is an outstanding tool for conducting research and policy analysis regarding children and young adults receiving SSI.     

HMOs for Medicaid: the road to financial independence is often poorly paved.

During the 1980s both the federal government and the private sector articulated policies to encourage the development and participation of health maintenance organizations (HMOs) in the Medicaid program. However, the policies, intended to save costs, limited the ability of new HMOs to achieve financial independence. New plans that emphasize Medicaid participation have few, if any, options on benefit design or in setting capitation rates. Relative to fee-for-service Medicaid programs, their costs to provide services may be quite high, as they have neither the buying power not the ability to impose discounts. As a consequence, plans must focus their financial planning efforts on targeting and attaining a stable enrollment base and on controlling the amount of services provided, tasks that are difficult for all HMOs. Achieving a stable enrollment base is particularly hard because Medicaid eligibles have few incentives to enroll and once enrolled often lose their Medicaid eligibility. Traditional HMOs control the amount of services provided through physician selection, financial incentives on physicians, and monitoring and utilization review. Lack of information and the difficulty inherent in attracting sufficient provider participation limit the first two strategies, so new plans often adopt organization structures that rely heavily on monitoring activities. Unfortunately, management information systems for HMOs are often the weakest link. We discuss the tasks and present data on financial planning, on putting financial plans into operation, and on monitoring progress toward financial independence for a set of ten demonstration projects sponsored by the Robert Wood Johnson Foundation.