Aki Roberts

Predictors of Homicide Clearance by Arrest An Event History Analysis of NIBRS Incidents

One perspective on homicide clearance by arrest argues that clearance is influenced by police discretion based on victim characteristics. Another suggests that immediate situational characteristics, related to physical evidence and information, are more important in clearing homicides. Using event history analysis, this study examined the effects of victim and situational characteristics on homicide clearance for 1579 murder incidents from the 2002 National Incident-Based Reporting System (NIBRS). Unlike the logistic regression approach typically used in murder clearance research, event history analysis considers the length of time to clearance, increasing the accuracy of estimates. The current analysis found that incidents with female or younger victims were more likely to be cleared. Also, homicides with victims involved in drug- and gang-related activities were more likely to be cleared. However, the significant impact of victim characteristics disappeared after controlling for situational variables related to physical evidence, information, and witnesses. Situational characteristics such as under-the-influence offenders, non-stranger offenders, contact weapons, and concomitant serious offenses significantly increased the odds of homicide clearance.

Hispanic Victims and Homicide Clearance by Arrest

When applied to homicide clearance by arrest, the victim-devaluing perspective posits that police favor higher—social status victims by allocating greater investigative effort to their cases. Previous studies have measured social status via a dichotomous race variable (White vs. Black, White vs. non-White, or non-Hispanic White vs. racial/ ethnic minority). As the Hispanic population grows in the United States, it is increasingly important to extend homicide clearance research beyond the traditional questions of dichotomous racial/ethnic differences. Using 2000-2007 homicide data from agencies that report victim’s ethnicity to the National Incident-Based Reporting System (NIBRS), the current study examines the impact of victim’s race/ethnicity on homicide clearance by arrest via a trichomotous measure (non-Hispanic White, non-Hispanic Black, or Hispanic). Event history analysis found that, controlling for other incident characteristics, homicides with Hispanic victims had a lower risk of clearance by arrest than those with non-Hispanic White or non-Hispanic Black v ictims.

Victim-Offender Racial Dyads and Clearance of Lethal and Nonlethal Assault

Previous clearance research provides an incomplete test of theories emphasizing the role of both victim and offender status in police discretion. Using National Incident Based Reporting System (NIBRS) data, we investigate the impact of both victims and offenders race, and, in particular, victim— offender racial dyads on homicide clearance by arrest, using event history (survival) analysis, so that time to clearance and censoring are considered. We also compare models for homicide clearance with those for aggravated assault. For homicides, results indicate that incidents with non-white offenders are more likely to be cleared by arrest than those with white offenders, regardless of victims race. In contrast, for aggravated assault, dyads are important: incidents involving white victims and offenders are most likely to be cleared, with incidents involving non-white parties least likely to be cleared. Furthermore, the impact of victim—offender racial dyads on clearance is smaller for homicide than for aggravated assault.

The Difference "Hate" Makes in Clearing Crime: An Event History Analysis of Incident Factors

Studying hate crime clearance rates provides an opportunity to uncover the factors that influence police effectiveness for a relatively new legal category—one that was designed ostensibly to protect minorities, and that may pose unique challenges for police reporting, defining, and investigation. Using multiple years (2005-2010) of data from the National Incident-Based Reporting System (NIBRS), we estimate event history models to compare the incident-level predictors and relative probability of arrest for hate and nonbias crimes. As an aggregate category, we find hate crimes are less likely to clear than nonbias crimes. However, the most prototypical hate crimes—White-on-non-White incidents motivated by racial and ethnic bias—are as likely to clear as the most successfully cleared nonbias crimes. Our results suggest that only hate crimes that fit popular constructions of “normal victims and offenders” receive investigative outcomes comparable with otherwise similar nonbias offenses.

Elements of Terrorism Preparedness in Local Police Agencies, 2003-2007: Impact of Vulnerability, Organizational Characteristics, and Contagion in the Post-9/11 Era

Different elements of local police agencies’ terrorism preparedness may be associated with different organizational/environmental variables. We use 2003-2007 data (showing considerable adoption and desistance of practices) on medium-to-large-sized local agencies to examine relationships between contingency (vulnerability, organizational characteristics) and contagion (network/isomorphic influence) measures and preparedness elements, including terrorism special units, dedicated assignment of personnel, terrorism-related community outreach, computerized intelligence files, and interagency-shared radio frequencies. Modeling 2007 preparedness revealed consistencies and some differences in the associations between these measures and the different preparedness elements. The finding of no association between objective vulnerability score and any terrorism preparedness action particularly warrants further research attention. It will also be important to extend preparedness research into the recent period of economic recession.

Impact of network ties on change in police agency practices

Purpose – Organizational research has suggested that network ties influence adoption of innovations and other organizational behavior. This paper aims to study the impact of network ties on change in police agency practices in a sample of city and county police agencies for which Weiss provided data on informal communication ties between agency planners.Design/methodology/approach – The authors analyzed change in six agency practices from 1997 to 2000, as indicated in law enforcement management and administrative statistics (LEMAS) data, with a variable indicating whether an agencys network contact engaged in the practice.Findings – Network ties appeared to influence change in computer use for crime mapping, with change more likely when the agency and its network contact initially differed with respect to the practice. Statistically significant network influences were not found for change in the other practices (existence of a formal community policing plan, geographic assignment of detectives, encourage...

Explaining Differences in Homicide Clearance Rates Between Japan and the United States

Japan maintains near-perfect homicide clearance rates (around 95%, compared with roughly 60% in the United States). This study explored possible explanations for higher homicide clearance rates in Japan than in the United States. Using recent (2000 to 2004) official summary statistics, this study found that Japanese homicides contain a higher proportion of “easy-to-clear” cases, including those with nonfirearm weapons, family member offenders, and child (and not teenager or young adult) victims, than do American homicides. Also the Japanese categorization of homicides in official statistics includes cases favorable to clearance (attempted homicide) and excludes cases unfavorable to clearance (robbery-homicide). These findings suggest caution in attributing Japans higher homicide clearance rates exclusively to police effectiveness or citizen–police cooperation. Suggestions for future multivariate research are also discussed.

Explaining Temporary and Permanent Motor Vehicle Theft Rates in the United States: A Crime-Specific Approach

Objectives: To apply crime-specific models based on differing potential offender pools and opportunity structures to temporary and permanent motor vehicle theft (MVT). Method: Using 310 U.S. cities with 50,000 or more residents, the current study developed and examined crime-specific multivariate models for temporary and permanent MVT rates. To evaluate the distinctiveness of crime-specific variables’ associations with each MVT type, the study also predicted each MVT rate via measures theoretically specific to the other. Results: Among temporary-specific variables, young male population and the percentage of households without a vehicle were positively associated with temporary MVT. Permanent-specific measures of adult male property offender pool size, percentage of households with high disposable income, unemployment, U.S.-Mexico border proximity, and auto-related businesses were associated with permanent MVT (though in an unexpected direction for disposable income). Some variables were associated with both types of MVT, but young male population was uniquely associated with temporary MVT while unemployment rate, distance to U.S.-Mexico border and number of auto-related businesses were specific to permanent MVT. Conclusions: Findings suggest that specific prevention approaches are needed for each type of MVT. Shortcomings of the research include potential misclassification of temporary and permanent MVT and lack of some potentially important opportunity variables.

Motor Vehicle Recovery A Multilevel Event History Analysis of NIBRS Data

Despite its importance for victims, and society as a whole, motor vehicle theft (MVT) recovery is rarely studied. The current research note draws on rational choice and opportunity-based perspectives, and police agency technology use, to develop and test a multilevel event history (survival) analysis model for MVT recovery. Contrary to the hypothesis that more expensive vehicles have a lower chance of recovery due to their attractiveness for permanent retention, the analysis found that recovery was least likely for incidents in which the stolen car had little value (less than

Adjusting rates of homicide clearance by arrest for investigation difficulty: modeling incident- and jurisdiction-level obstacles

1,000), with no significant differences among the categories of