Berk, Richard A

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Now showing 1 - 3 of 3
  • Publication
    Developing a Practical Forecasting Screener for Domestic Violence Incidents
    (2005-01-25) Berk, Richard A; Sorenson, Susan B; He, Yan
    In this paper, we report on the development of a short screening tool that deputies in the Los Angeles Sheriff's Department could use in the field to help forecast domestic violence incidents in particular households. The data come from over 500 households to which sheriff's deputies were dispatched in the fall of 2003. Information on potential predictors was collected at the scene. Outcomes were measured during a three month follow-up. The data were analyzed with modern data mining procedures in which true forecasts were evaluated. A screening instrument was then developed based on a small fraction of the information collected. Making the screening instrument more complicated did not improve forecasting skill. Taking the relative costs of false positives and false negatives into account, the instrument correctly forecasted future calls for service about 60% of the time. Future calls involving domestic violence misdemeanors and felonies were correctly forecast about 50% of the time. The 50% figure is especially important because such calls require a law enforcement response and yet are a relatively small fraction of all domestic violence calls for service. A number of broader policy implications follow. It is feasible to construct a quick-response, domestic violence screener that is practical to deploy and that can forecast with useful skill. More informed decisions by police officers in the field can follow. Although the same kinds of predictors are likely to be effective in a wide variety of jurisdictions, the particular indicators selected will vary in response to local demographics and the local costs of forecasting errors. It is also feasible to evaluate such quick-response threat assessment tools for their forecasting accuracy. But, the costs of forecasting errors must be taken into account. Also, when the data used to build the forecasting instrument are also used to evaluate its accuracy, inflated estimates of forecasting skill are likely.
  • Publication
    The Legalization of Abortion and Subsequent Youth Homicide: A Time Series Analysis
    (2003-12-01) Berk, Richard A; Sorenson, Susan B; Weib, Douglas J; Upchurch, Dawn M
    In this article, we examine the association between the legalization of abortion with the 1973 Roe v. Wade decision and youth homicide in the 1980s and 1990s. An interrupted time series design was used to examine the deaths of all U.S. 15- to 24-year-olds that were classified as homicides according to the International Classification of Diseases (codes E960-969) from 1970 to 1998. The legalization of abortion is associated over a decade later with a gradual reduction in the homicides of White and non-White young men. The effect on the homicides of young women is minimal. We conclude that the 1990s decline in the homicide of young men is statistically associated with the legalization of abortion. Findings are not consistent with several alternative explanations, such as changes in the crack cocaine drug market. It is almost inconceivable that in the United States of today, policies affecting the choice to have children would be justified as a means to control crime. Yet, if the legalization of abortion had this unintended effect, the full range of policy implications needs to be discussed.
  • Publication
    Legalized Abortion and the Homicide of Young Children: An Empirical Investigation
    (2002-12-01) Sorenson, Susan B; Berk, Richard A; Wiebe, Douglas J
    Recent research has drawn a link, sometimes a causal link, between the legalization of abortion in the late 1960s and early 1970s and the precipitous decline in crime in the 1990s. Abortion is posited to have reduced the number of potential victims and potential perpetrators, and the potential effect is examined when these individuals would be reaching their high-crime years. We examined a more proximal potential association between legalized abortion and homicide, specifically, the homicide of young children. Assuming that abortions occurred when the family had insufficient resources for the birth, one could hypothesize that children would have been at higher risk of homicide if born into these circumstances. We examined 1960-1998 U.S. mortality data for children under 5 years of age using an interrupted time series design. The legalization of abortion was not associated with a sudden change in child homicide trends. It was, however, associated with a steady decrease in the homicides of toddlers (i.e., 1- to 4-year-olds) in subsequent years. Although in the predicted direction, the decrease in homicides of children under 1 year of age was not statistically significant. Competing explanations that could be examined in the data (e.g., changes in mortality classification) do not account for the findings.