LOCATING THE VANGUARD IN RISING AND FALLING HOMICIDE RATES ACROSS U.S. CITIES*

This research examines trends in U.S. homicide rates at the city level during the so‐called homicide epidemic in the latter decades of the 20th century. Using spline regression techniques to locate structural breaks in city‐level time series, we model the true trends of homicide rates to identify those cities that exhibited a meaningful boom and bust cycle. We then use Tobit regressions for all cities at risk of experiencing a cycle to estimate unbiased effects of theoretically important predictors on the timing of the phase changes. Our findings reveal that larger cities were more likely to experience an epidemic‐like pattern, and that densely populated cities characterized by high levels of deprivation tended to exhibit the rise and fall in homicide rates earlier than other cities.     

STRUCTURAL COVARIATES OF U.S. COUNTY HOMICIDE RATES: INCORPORATING SPATIAL EFFECTS*

Spatial analysis is statistically and substantively important for macrolevel criminological inquiry. Using county‐level data for the decennial years in the 1960 to 1990 time period, we reexamine the impact of conventional structural covariates on homicide rates and explicitly model spatial effects. Important findings are: (1) homicide is strongly clustered in space; (2) this clustering cannot be completely explained by common measures of the structural similarity of neighboring counties; (3) noteworthy regional differences are observed in the effects of structural covariates on homicide rates; and (4) evidence consistent with a diffusion process for homicide is observed in the South throughout the 1960–1990 period.     

A deterrence study of the death penalty in Illinois, 1933–1980

The study analyzes the effect of executions and the death penalty on homicides in Illinois. A forty-eight year time series (1933–1980 inclusive) is used as the basis for this analysis. The first series of results are presented in a graph of executions and homicides by year. A second portion of the analysis compares the mean homicide rates for three time periods—years with executions, years when the death penalty was allowed but no executions were performed, and years in which the death penalty was abolished by the U.S. Supreme Court. No notable differences in homicide rates were observed for these three eras. Finally, a regression analysis was performed which included a lag structure and several relevant controls. The deterrence measure (executions) made no contribution to the variation in homicide rates. Thus, the authors conclude that there is no deterrent effect for the death penalty on homicides in Illinois.     

POLICING,DRUGS, AND THE HOMICIDE DECLINE IN NEW YORK CITY IN THE 1990s*

This research reassesses the role of policing and drugs in the sharp homicide decline in New York City in the 1990s. Drawing on theoretical arguments about “broken windows” policing and lethal violence associated with the diffusion of crack cocaine, we estimate the effects of measures of misdemeanor arrests and cocaine prevalence on homicide rates with pooled, cross‐sectional time‐series data for 74 New York City precincts over the 1990–1999 period. The results of mixed regression models reveal a significant negative effect of changes in misdemeanor arrests and a significant positive effect of changes in cocaine prevalence on changes in total homicide rates. Additional analyses of homicide disaggregated by weapon indicate that the effects of misdemeanor arrests and cocaine prevalence emerge for gun‐related but not for non‐gun‐related homicides. Overall, the research generally supports influential interpretations of the homicide decline in New York City but also raises questions about underlying mechanisms that warrant more inquiry in future research.     

National study comparing the characteristics of patients diagnosed with schizophrenia who committed homicide vs. those who died by suicide

Associations between serious mental disorder and violence are well-documented, but there is little epidemiological evidence linking these disorders and homicide risk. The reported study compares socio-demographic and clinical characteristics of people diagnosed with schizophrenia who committed homicide vs. those who died by suicide. The study is a national case series of male patients in England & Wales diagnosed with schizophrenia and convicted of homicide during 1997–2012 (n = 168), and a randomly selected comparison group of male patients with schizophrenia who died by suicide and who were matched to the homicide case series by age (n = 777). There are different patterns of behaviour in people with schizophrenia preceding homicide and suicide. Homicide perpetrators have frequently disengaged with services whilst patients who die by suicide are often in recent contact. This is important knowledge for clinical services as it indicates a different preventive emphasis despite the existence of other shared characteristics.     

A Qualitative Assessment of Stress Perceptions Among Members of a Homicide Unit

Existing research on stress among police assumes the presence of uniform stressors across job roles and borrows upon generic stress instruments to tap stress types and levels. The present study draws upon interviews with 26 members of a metropolitan homicide unit to provide an inductive vantage point on stress perceptions within a specialized area of policing. We provide evidence that the occupational and organizational forms of stress detailed by these officers are shaped largely by the unique nature of homicide work. Among the unique task-related stressors observed include the complexities of homicide crime scenes, time pressures, cases assignment factors, paperwork demands, and long-term ownership over individual case files. A series of structural issues from both within and outside the police agency are identified as organizational stressors unique to homicide work. We conclude with a proposed theory of homicide investigator stress and implications for future research.     

The murder-suicide. A study of the postagressional suicide

The authors studied a series of 18 cases of homicide followed by suicide or attempted suicide by the aggressor, analyzing: 1) the frequency of such acts; 2) the age and sex of the aggressors; 3) the means or arms used for the murder and suicide; 4) the period of time between the two events; and 5) the motives for the homicides and the relationship between the victims and their aggressors.     

Canadian firearms legislation and effects on homicide 1974 to 2008

Canada has implemented legislation covering all firearms since 1977 and presents a model to examine incremental firearms control. The effect of legislation on homicide by firearm and the subcategory, spousal homicide, is controversial and has not been well studied to date. Legislative effects on homicide and spousal homicide were analyzed using data obtained from Statistics Canada from 1974 to 2008. Three statistical methods were applied to search for any associated effects of firearms legislation. Interrupted time series regression, ARIMA, and Joinpoint analysis were performed. Neither were any significant beneficial associations between firearms legislation and homicide or spousal homicide rates found after the passage of three Acts by the Canadian Parliament--Bill C-51 (1977), C-17 (1991), and C-68 (1995)--nor were effects found after the implementation of licensing in 2001 and the registration of rifles and shotguns in 2003. After the passage of C-68, a decrease in the rate of the decline of homicide by firearm was found by interrupted regression. Joinpoint analysis also found an increasing trend in homicide by firearm rate post the enactment of the licensing portion of C-68. Other factors found to be associated with homicide rates were median age, unemployment, immigration rates, percentage of population in low-income bracket, Gini index of income equality, population per police officer, and incarceration rate. This study failed to demonstrate a beneficial association between legislation and firearm homicide rates between 1974 and 2008.     

Violence and the U.S. prohibitions of drugs and alcohol

This paper examines the relation between prohibitions and violence,using the historical behavior of the homicide rate in the UnitedStates. The results document that increases in enforcement ofdrug and alcohol prohibition have been associated with increasesin the homicide rate, and auxiliary evidence suggests this positivecorrelation reflects a causal effect of prohibition enforcementon homicide. Controlling for other potential determinants ofthe homicide rate does not alter the conclusion that drug andalcohol prohibition have substantially raised the homicide ratein the U.S. over much of the past 100 years.     

ECONOMIC INEQUALITY AND LEVELS OF HOMICIDE: AN ANALYSIS OF URBAN NEIGHBORHOODS*

This paper presents an analysis of the relationship between levels of economic inequality and homicide rates for a sample of 26 neighborhoods in Manhattan, New York. It argues that neighborhoods are more appropriate units of analysis for studying inequality and homicide than are larger political and statistical units because neighborhoods are more likely to constitute meaningful frames of reference for social comparisons. The principle hypothesis is that a high degree of economic inequality in a neighborhood will give rise to high levels of relative deprivation and high rates of homicide. The results of a series of multiple regression analyses fail to support this hypothesis. The measure of economic inequality is weakly associated with the observed homicide rates. Similarly, the racial composition of Manhattan neighborhoods exhibits no significant association with levels of homicide, given statistical controls for other sociodemographic variables. Two neighborhood characteristics do emerge as significant predictors of homicide rates: the relative size of the poverty population and the percent divorced or separated. Homicide rates tend to be highest in those neighborhoods characterized by extreme poverty and pervasive marital dissolution.     

The First Delinquent Peers Are the Most Important: Examining Nonlinearity in the Peer Effect

Criminologists have long recognized the importance of peers in the etiology of delinquency. Yet, the bulk of empirical studies on this topic make the implicit assumption that the peer effect to be conditioned is linear. With few notable exceptions, prior criminological research has not thought deeply about possible nonlinearity in the peer effect. To address this issue, the present study examines whether the functional form of the relationship between peer and respondent smoking, getting drunk, and fighting is nonlinear, and whether this nonlinearity is moderated by lagged respondent delinquency. Logistic regression models on adolescents from The National Longitudinal Study of Adolescent Health indicate that the marginal effect of peer delinquency on respondent delinquency decreases as the count of delinquent friends increases, consistent with a satiation effect. Moreover, the models indicate that the nonlinear effect of peer delinquency on respondent delinquency is moderated by prior respondent delinquency.     

A COMPARISON OF CHANGES IN POLICE AND GENERAL HOMICIDES: 1930–1998*

This paper presents a new data series for homicides of law enforcement officers. Available for more than two centuries, it is much longer than series previously examined. Police killings had two extreme peaks, one in the 1920s and another in the 1970s. We use the post‐1930 part of the series in a time‐series regression to explore structural conditions that affect police killings in the short term. Economic conditions, prison populations, and World War II have considerably larger impacts on police killings than on homicide generally. Police killings are less affected by demographic changes and by the crack epidemic.     

THE SHORT‐TERM EFFECTS OF EXECUTIONS ON HOMICIDES: DETERRENCE,DISPLACEMENT, OR BOTH?*

Does the death penalty save lives? In recent years, a new round of research has been using annual time‐series panel data from the 50 U.S. states for 25 or so years from the 1970s to the late 1990s that claims to find many lives saved through reductions in subsequent homicide rates after executions. This research, in turn, has produced a round of critiques, which concludes that these findings are not robust enough to model even small changes in specifications that yield dramatically different results. A principal reason for this sensitivity of the findings is that few state‐years exist (about 1 percent of all state‐years) in which six or more executions have occurred. To provide a different perspective, we focus on Texas, a state that has used the death penalty with sufficient frequency to make possible relatively stable estimates of the homicide response to executions. In addition, we narrow the observation intervals for recording executions and homicides from the annual calendar year to monthly intervals. Based on time‐series analyses and independent‐validation tests, our best‐fitting model shows that, from January 1994 through December 2005, evidence exists of modest, short‐term reductions in homicides in Texas in the first and fourth months that follow an execution—about 2.5 fewer homicides total. Another model suggests, however, that in addition to homicide reductions, some displacement of homicides may be possible from one month to another in the months after an execution, which reduces the total reduction in homicides after an execution to about .5 during a 12‐month period. Implications for additional research and the need for future analysis and replication are discussed.     

Applying Time-series Cross Correlation Analysis to Examine the Nexus between Firearms and Homicide in Hong Kong

This paper applied time series analysis to examine the nexus between firearm robberies and homicide in Hong Kong Special Administrative Region (HK). Recent years have seen a reduction in firearm related offences in HK compared to Britain. For instance, only three cases of firearm robbery in 2004 in HK (0.1% of all robbery; 2,237 incidents) involved genuine firearms, compared to 4,117 firearm robbery incidents (4% of all robbery) in Britain in the same year. This paper established a cross-correlation coefficient of 0.50 at lag 0 for the annual rate of two serious crimes, genuine firearm robbery and homicide, after identifying an ARMA(1,0) model from each time series (1972–2002). The results suggest that the prevalence of firearm robbery is moderately associated with the prevalence of homicide in HK.

Time Series Analysis of Crime Rates

A methodological critique of Cantor and Land's (1985) approach to the time series analysis of the crime–unemployment relationship is developed. Error correction models for U.S. homicide and robbery rates for the years 1946–1997 are presented to illustrate procedures for analyzing nonstationary time series data. The critique is followed by a discussion of methodological problems in work by Devine et al. (1988), Smith et al. (1992), and Britt (1994, 1997) that builds on Cantor and Land's approach.     

Homicide as Infectious Disease: Using Public Health Methods to Investigate the Diffusion of Homicide

This study examined the spatial and temporal movement of homicide in Newark, New Jersey from January 1982 through September 2008. We hypothesized that homicide would diffuse in a similar process to an infectious disease with firearms and gangs operating as the infectious agents. A total of 2,366 homicide incidents were analyzed using SaTScan v.9.0, a cluster detection software. The results revealed spatio-temporal patterns of expansion diffusion: overall, firearm and gang homicide clusters in Newark evolved from a common area in the center of the city and spread southward and westward over the course of two decades. This pattern of movement has implications in regards to the susceptibility of populations to homicide, particularly because northern and eastern Newark remained largely immune to homicide clusters. The theoretical and practical implications of the findings, as well as recommendations for future research, are discussed.     

The Spatial Patterning of County Homicide Rates: An Application of Exploratory Spatial Data Analysis

The possibility that homicides can spread from one geographic area toanother has been entertained for some time by social scientists, yetsystematic efforts to demonstrate the existence, or estimate the strength,of such a diffusion process are just beginning. This paper uses exploratoryspatial data analysis (ESDA) to examine the distribution of homicides in 78counties in, or around, the St. Louis metropolitan area for two timeperiods: a period of relatively stable homicide (1984–1988) and aperiod of generally increasing homicide (1988–1993). The findingsreveal that homicides are distributed nonrandomly, suggestive of positivespatial autocorrelation. Moreover, changes over time in the distribution ofhomicides suggest the possible diffusion of lethal violence out of onecounty containing a medium-sized city (Macon County) into two nearbycounties (Morgan and Sangamon Counties) located to the west. Althoughtraditional correlates of homicide do not account for its nonrandom spatialdistribution across counties, we find some evidence that more affluentareas, or those more rural or agricultural areas, serve as barriers againstthe diffusion of homicides. The patterns of spatial distribution revealedthrough ESDA provide an empirical foundation for the specification ofmultivariate models which can provide formal tests for diffusion processes.     

Examining Space–Time Interaction in City-Level Homicide Data: Crack Markets and the Diffusion of Guns Among Youth

This paper examines the linkage between crack market activity and gunhomicide suggested by Blumstein (1995), who argues that the arrival ofcrack stimulated an increased availability of guns among juveniles. Thisgreater availability of guns, the argument continues, is responsible for thesharp upswing in juvenile homicide experienced in the United States in themid-1980s. Using city-level data on crack arrests and gun-related juvenilehomicide, we fit a change-point version of the Bass (1969) model ofinnovation diffusion. We find that, in most large American cities, thediffusion process for crack cocaine experienced an onset of dramatic growththat was followed by a similar, slightly slower growth in gun homicidescommitted by juveniles. We further use cluster analysis to find that thespatial patterning of the two processes is similar, starting on the East andWest Coasts and working their way toward other regions of the nation. Gunuse in homicide among slightly older offenders (ages 18–24) alsoexperienced a change at roughly the same time as the juveniles, but the rateof diffusion was considerably milder than for the younger group; offendersages 25 or older generally show no growth in gun-related homicide whatsoever. In addition, there is no detectable surge in juvenile nongun homicide activity. Based on these findings, we conclude that the crack cocaine markets–gun availability linkage is highly plausible, and we suggest directions for future research in clarifying the dynamics of the late-1980s surge in juvenile homicide.     

Trajectories of non-intimate partner and intimate partner homicides, 1980-1999: The importance of rurality

Research had consistently shown that intimate partner homicide rates had been on a steady downward decline over the past two decades; however, a relatively recent movement in intimate partner homicide research had emphasized the need for further dissecting the aggregate trends by factors such as gender, race, victim-offender relationship, and same-sex partners. Taking this a step forward, this study utilized trajectory analysis for comparing and contrasting non-intimate partner homicide and intimate partner homicide rates over time in order to explore the importance of rurality when investigating intimate partner violence. Results of the analysis indicated that although intimate partner homicide rates had been declining over the 1980-1999 period for the majority of the 1,341 U.S. counties examined, there was evidence that rurality was significantly associated with an increased likelihood of assignment to a non-declining intimate partner homicide trajectory. In light of the findings, the authors also consider how these results can direct future research on intimate partner violence in rural areas.     

Unemployment and Crime: Toward Resolving the Paradox

While official crime statistics from many countries show that unemployed people have high crime rates and that communities with a lot of unemployment experience a lot of crime, this cross-sectional relationship is very often not found in time-series studies of unemployment and crime. In Australia there have been no individual-level or cross-sectional studies of unemployment and adult crime which have failed to find a positive relationship and no time-series which have supported a positive relationship. Consistent with this pattern, a time series of homicide from 1921 to 1987 in Australia reveals no significant unemployment effect. A theoretical resolution of this apparent paradox is advanced in terms of the effect of female employment on crime in a partriarchal society. Crime is posited as a function of both total unemployment and female employment. When female employment is added to the model, it has a strong positive effect on homicide, and unemployment also assumes a strong positive effect.