Police patrol and the deterrence of crime

A nonrecursive model of the deterrent effect of police presence was formulated and tested for 26 cities. Victimization data were employed as measures of crime, unpublished FBI data on the number of police patrol units as the measure of levels of police presence, and data for 11 exogenous variables were derived from FBI and census reports. It was found that per capita, police are a positive function of rates of violent crime and that clearance rates are a positive function of police presence. However, some offenses that have traditionally been thought to be deterrable are not inversely related to clearance rates. The equations were re-estimated using official measures of crime and found to be more consistent with the deterrent hypothesis. It is suggested that official data may generate a spurious correlation. Finally, caution is suggested in consideration of alternative forms of police presence.     

CRIME AND THE POLICE A Multivariate Analysis

In an effort to assess the correlates of the variations in the rate of crime aggregated at a city level, data are analyzed using multiple correlation analysis that includes indicators of socioeconomic and social control (police) characteristics of the cities The results indicate that the rate of police and money budgeted to police contributes little to the explained variation in rates of crime. In addition, these indicators of social control variations do not correlate with variations in clearance rates The data are interpreted in terms of their implications for public policy, evaluation of police, and deterrence theory.     

The relationship of criminal victimization,police per capita and population density in twenty-six cities

This study examines the relationship between indicators of environmental control and criminal victimization rates in twenty-six large American central cities. Using a typology of criminal victimization that classifies crimes as property crimes with contact, property crimes without contact, and nonproperty assaultive crimes, it is found that both the number of police per capita and population density are negatively related to property crimes without contact and nonproperty assaultive crimes. However, the number of police per capita (controlling for population density) is not related to property crimes with contact, while population density (controlling for number of police per capita) is positively related to these crimes. Possible explanations for these patterns of relationships are discussed.     

Liberal versus conservative public policies on crime: What was the comparative track record during the 1990s?

The purpose of this study was to examine the efficacy of social control and social support policies associated with conservative and liberal political ideologies with respect to violent crime in large U.S. cities during the 1990s. Eighty-five cities with populations of 150,000+ were included in the analysis; these cities accounted for fifty-two million urban area residents of the U.S. The use of the two-way, fixed-effect panel data method of statistical analysis enabled the authors to assess the relationship between change in local government expenditures for police and court services (social control) and expenditures on community development and park/recreation (support policy) and corresponding changes in crime rates documented within these cities. The findings indicated that expenditure on both police services and community development initiatives had significantly suppressive effects on crime in these cities during the period of the 1990s. It appeared that both conservative and liberal policies had their merits as effective countermeasures to crime.     

The electoral budget cycle on municipal police expenditure

This paper analyzes the effects of electoral cycles on municipal police expenditure. We use a database with information on Spanish municipalities with more than 20,000 inhabitants for the period 2001–2008. Our data show that incumbents increase police spending 1 year before the elections, thus we confirm an electoral budget cycle on police expenditure in Spain. We also find that conservative parties are associated with increased spending on public safety. Population has a positive and significant impact on police expenditures per capita, which indicates diseconomies of scale. The theory on sub-national government spending shows that intergovernmental transfers per capita and taxes per capita are believed to impact local expenditures. Our model fits this assumption, showing a significant and positive influence of both variables on police expenditures. Finally, our model reports a positive impact of both immigration and economic level on police spending.     

The Murder Mystery: Police Effectiveness and Homicide

Objective

Previous aggregate analyses of the effect of police on crime show that increases in police staffing are especially effective at preventing homicide. This conflicts with evidence that suggests standard police methods should be more effective at preventing robbery, auto theft, and other property crimes. My objective is to reconcile the two.

Methods

Regression of crime rates on uniformed police staffing and other economic and demographic covariates, for a panel of 59 US cities for the period 1970–2013.

Results

Lagged crime rates are strong and statistically significant predictors of both policing staffing and crime rates, particularly homicide. When lags are included in the specification, the apparent effect of police on homicide drops by more than 70 %; there is little change in the effect of police on other crimes. Findings are robust with respect to specification and method.

Conclusions

Previous studies omitted lags and overstated the effectiveness of police on homicide. Because murder accounts for almost 40 % of all costs of crime in US cities, it is no longer clear whether increasing police force size is a cost-effective way to cut crime. Improving police tactics is more likely to work and less expensive.

     

The Effects of Immigrant Concentration on Changes in Neighborhood Crime Rates

Objectives

This study investigated the extent to which immigrant concentration is associated with reductions in neighborhood crime rates in the City of Los Angeles.

Methods

A potential outcomes model using two-stage least squares regression was estimated, where immigrant concentration levels in 1990 were used as an instrumental variable to predict immigrant concentration levels in 2000. The instrumental variables design was used to reduce selection bias in estimating the effect of immigrant concentration on changes in official crime rates between 2000 and 2005 for census tracts in the City of Los Angeles, holding constant other demographic variables and area-level fixed effects. Non-parametric smoothers were also employed in a two-stage least squares regression model to control for the potential influence of heterogeneity in immigrant concentration on changes in crime rates.

Results

The results indicate that greater predicted concentrations of immigrants in neighborhoods are linked to significant reductions in crime. The results are robust to a number of different model specifications.

Conclusions

The findings challenge traditional ecological perspectives that link immigrant settlement to higher rates of crime. Immigration settlement patterns appear to be associated with reducing the social burden of crime. Study conclusions are limited by the potential for omitted variables that may bias the observed relationship between immigrant concentration and neighborhood crime rates, and the use of only official crime data which may under report crimes committed against immigrants. Understanding whether immigrant concentration is an important dynamic of changing neighborhood patterns of crime outside Los Angeles will require replication with data from other U.S. cities.     

THE EFFECTS OF LOCAL LAW ENFORCEMENT BLOCK GRANTS ON SERIOUS CRIME*

Research Summary The Local Law Enforcement Block Grants (LLEBG) Program was second only to the Community‐Oriented Policing Services (COPS) Program in its funding levels. Some $3 billion was dispensed to local jurisdictions to reduce crime and improve public safety; yet the effects of LLEBG funding on crime have been all but ignored. Accordingly, panel data from more than 5,000 cities covering a 12‐year period (1990–2001) were collected, and index crime rates were regressed on LLEBG funding and appropriate demographic controls. Additional controls for police levels and other federal grants were also introduced, proper checks for endogeneity of grants (and police levels) were performed, and the models were subjected to an array of robustness checks. A consistent message emerged: LLEBG Program funding was associated with significant reductions in serious crime. Policy Implications Although LLEBG funding seemed to reduce serious crime, the results also revealed that the decrease did not occur through the hiring of additional police officers, even though many funds were used for that purpose. Other mechanisms were thus at work, but the data did not provide insights into what these mechanisms were. In any case, every $1 in LLEBG funding per capita was associated with approximately 59 fewer index crimes per 100,000 people. When combined with the findings from recent studies of the effects of community policing grants on crime, this study suggests additional federal support for local law‐enforcement agencies should be considered.     

A longitudinal analysis of the arrest-crime relationship: A further examination of the tipping effect

This study examines the contextual effect of arrest clearance rates, over time, on the arrest-crime relationship. The bivariate autoregressive integrated moving average (ARIMA) analyses of monthly crime and arrest data for seven Pennsylvania cities for robbery, burglary, larceny, and auto theft suggest that the deterrent effect of arrests on crime is probably limited to smaller cities whose police department are able to clear an appreciable proportion of crimes over time, through arrests.     

Establishing the statistical relationship between population size and UCR crime rate: Its impact and implications

The fact that the volume of crime is related to the size of a jurisdiction's population has been well established. The relationship between crime rate and population size, however, is less clear. Crime rate presents crime on a per capita basis, and is intended to adjust for population size so that comparisons can be made. In this article, the author first establishes the statistical relationship between crime rate and population size. Once established, he conducted an analysis of crime rates in jurisdictions of various sizes and in a variety of population-based strata using data obtained from the Uniform Crime Reports (UCR). Based on his findings, the author discusses implications for research and analysis, database management, and making jurisdictional comparisons of crime rates.     

Local politics and police strength

Numerous studies have explored variation in police employment across cities, usually focusing on public choice, conflict, or organizational explanations. Yet, few consider whether the local political context affects police employment. Recent research suggests that local politics affects criminal justice outcomes. Using insights from urban politics research, I develop testable hypotheses about the effects of local political arrangements on municipal police strength. WLS regression results suggest the value of considering local political context in models of police strength. Specifically, in a sample of 945 cities with 25,000 or more residents in 1990, net of other variables, cities with unreformed political systems (mayor‐council forms of government, district‐based city councils and partisan elections) had more police employees per 1,000 residents, and this effect varied by region. Additionally, the effect of minority populations and crime rates on police strength varied across municipal political contexts. Implications for theories of police strength are discussed.     

Police,Crime and the Problem of Weak Instruments: Revisiting the “More Police,Less Crime” Thesis

Objectives

A key question in the general deterrence literature has been the extent to which the police reduce crime. Definitive answers to this statement, however, are difficult to come by because while more police may reduce crime, higher crime rates may also increase police levels, by triggering the hiring of more police. One way to help overcome this problem is through the use of instrumental variables (IV). Levitt, for example, has employed instrumental variables regression procedures, using mayoral and gubernatorial election cycles and firefighter hiring as instruments for police strength, to address the potential endogeneity of police levels in structural equations of crime due to simultaneity bias.

Methods

We assess the validity and reliability of the instruments used by Levitt for police hiring using recently-developed specification tests for instruments. We apply these tests to both Levitt’s original panel dataset of 59 US cities covering the period 1970–1992 and an extended version of the panel with data through 2008.

Results

Results indicate that election cycles and firefighter hiring are “weak instruments”—weak predictors of police growth that, if used as instruments in an IV estimation, are prone to result in an unreliable estimate of the impact of police levels on crime.

Conclusions

Levitt’s preferred instruments for police levels—mayoral and gubernatorial election cycles and firefighter hiring—are weak instruments by current econometric standards and thus cannot be used to address the potential endogeneity of police in crime equations.

     

PRODUCING PERSONAL SAFETY: THE EFFECTS OF CRIME RATES, POLICE FORCE SIZE, AND FEAR OF CRIME

Aggregate data from a sample of 23 Canadian cities are used to examine relationships among crime rates, police staffing rates, fear of crime, and citizens'crime prevention behaviors. Bivariate and path analyses reveal positive correlations between fear of crime and parallel production (crime prevention behaviors) and negative impacts of police force size on such behaviors. Crime rates have both direct and indirect positive effects (via fear of crime) on parallel production. while police force size does not have any real effect on fear of crime.     

Crime,detection rate,and the police: A macro approach

Dutch criminality and its relation to the performance of police and justice have only recently been analyzed at the macro level (e.g., at the level of municipalities or the whole country). This type of approach is a useful supplement to analyses at the micro level (that of individuals), which are more common in Dutch empirical criminological research. The main results of such a macro approach are presented in this article. We conclude that the per capita numbers of youth, divorced people, and unemployed contribute significantly to the crime rate. The police strength and solving rates are important factors as well. Analysis of the production process of the police reveals that detecting one more case of driving under the influence is far more expensive than solving one more other crime or handling one more traffic accident. The results are combined to sketch a cost-benefit approach of different strategies in allocating more resources to the police. Allocating extra resources to solving more cases of vandalism gives the best cost-benefit ratio.     

Conclusions from the history of research into the effects of police force size on crime—1968 through 2013: a historical systematic review

Objectives

We describe and explain how the findings from nonexperimental studies of the relationship between police force size and crime have changed over time.

Methods

We conduct a systematic review of 62 studies and 229 findings of police force size and crime, from 1971 through 2013. Only studies of U.S. policing and containing standard errors of estimates were included. Using the robust variance estimation technique for meta-analysis, we show the history of study findings and effect sizes. We look at the influence of statistical methods and units of analysis, and time period of studies’ data, as well as variation in police force size over time.

Results

Findings vary considerably over time. However, compared to research standards and in comparison to effect sizes calculated for police practices in other meta-analyses, the overall effect size for police force size on crime is negative, small, and not statistically significant. Changes in research methods and units of analysis cannot account for fluctuations in findings. Finally, there is extremely little variation in police force size per capita over time, making it difficult to estimate the relationship with reliability.

Conclusions

This line of research has exhausted its utility. Changing policing strategy is likely to have a greater impact on crime than adding more police.

     

Investigating the Reliability of the Violent Crime Linkage Analysis System (ViCLAS) Crime Report

The Violent Crime Linkage Analysis System (ViCLAS) is a computerized investigative aid, developed by the Royal Canadian Mounted Police, which is used to increase information sharing and enable crime linkages in serious crime investigations. The current study examines the reliability of the ViCLAS Crime Report by calculating the level of agreement among two samples of police officers who received one of two fictitious crime scenarios; homicide (n = 116) or sexual assault (n = 121). Results from this study show that the observed inter-rater reliability among police officers completing the ViCLAS booklet was 79.30% for the homicide scenario, and 87.70% for the sexual assault scenario. Implications of the results are discussed.     

IN SEARCH OF A LINKAGE

Previous research has produced conflicting findings concerning the relationship between police evaluation by citizens and unreported crime rate. Data for thirteen large American cities indicate a weak positive relationship between the two variables. Strong negative relationships are evident between unreported crime rate and variables measuring police systems activities and demographic characteristics. Cities with the highest levels of police expenditures and manpower have the lowest levels of unreported crime, as do cities with high percentages of nonwhites and dense populations. Further analysis reveals that controlling for percentage of nonwhites and police manpower severely attenuates the original correlation between unreported crime rate and police evaluation. We conclude that future research should endeavor to explain the linkage between police systems activities and unreported crime.     

ANALYZING URBAN CRIME DATA: Deterrence and the Limitations of Arrests per Offense Ratios

Police reports of Index crimes, arrests, and population estimates for 1960 through 1977 for 49 U.S. cities are used to compare trends in arrest rates, crime rates, and the arrests per crime (A/C) ratio-a measure sometimes correlated with crime rates to assess the deterrent effect of arrest. Since the correlation of the A/C ratio with the crime rate can produce tautological results in a trend analysis. comparisons of trends for crime rates and arrest rates for specific cities are examined. The results do not support a deterrence hypothesis. but indicate that the A/C ratios for some of the nation's largest cities are unstable over time and sensitive to changes in reporting practices. The analysis illustrates the pitfalls encountered when data limitations are overlooked and underscores the need for more dependable measures of crime, apprehension, and punishment.     

The Etiology of Juvenile Delinquency: The United States and Switzerland Compared

Both Switzerland and the United States are highly affluent societies and rank consistently among the top five countries in the world in per capita income, both are Western democracies, both are highly urbanized, and both are highly industrialized. Thus, it is quite surprising to discover that Switzerland has much lower rates of crime and delinquency than is the case for the United States, a fact which is especially true for violent crimes. This paper attempts to explain the sources of the differences in crime rates between the two countries and gives special attention to a comparison of juvenile misconduct in the two countries.

In the first section, difficulties are discussed concerning the measurement of crime and delinquency in Switzerland, a country which collects few data on social problems in general. Some general trends are shown to be clear, however, including marked increases in drug abuse and suicide cases among the young in Switzerland. In the subsequent section, previous explanations of crime in Switzerland as compared to the United States are reviewed with special emphasis on Clinard's famous Cities with Little Crime: The Case of Switzerland (1978). The limitations of earlier interpretations are considered in detail. Finally, this paper ends by generating a set of theoretically and practically informed hypothesis for explaining the differences in crime rates between the two countries. It is hoped that these hypotheses will form the basis for more detailed research in the future.