Robert M. O'Brien

The Determinants of Deadly Force: A Structural Analysis of Police Violence

Political or threat explanations for the states use of internal violence suggest that killings committed by the police should be greatest in stratified jurisdictions with more minorities. Additional political effects such as race of the citys mayor or reform political arrangements are examined. The level of interpersonal violence the police encounter and other problems in departmental environments should account for these killing rates as well. Tobit analyses of 170 cities show that racial inequality explains police killings. Interpersonal violence measured by the murder rate also accounts for this use of lethal force. Separate analyses of police killings of blacks show that cities with more blacks and a recent growth in the black population have higher police killing rates of blacks, but the presence of a black mayor reduces these killings. Such findings support latent and direct political explanations for the internal use of lethal force to preserve order.

Estimating the Reliability of Aggregate-Level Variables Based on Individual-Level Characteristics:

Social scientists often use the mean of individual-level characteristics to describe aggregates such as organizations, schools, or programs. They seldom, however, attempt to assess the reliability of these measures. This article indicates how the internal consistency reliability of such measures can be estimated for several commonly used research designs. The method is based on generalizability theory and requires only the data that would normally be used to answer the substantive questions of a study; for example retests or parallel forms are not necessary.

The enduring effects of cohort characteristics on age-specific homicide rates, 1960-1995

In the past decade, young people in the United States have been two to three times more likely than in the two previous decades to commit homicides, while those 25 years and older have been less likely to commit homicides than were members of their age groups in the earlier time period. These changes in youth homicide rates are associated with two cohort characteristics that are theoretically linked to criminality: relative size of cohorts and the percentage of cohort members born to unwed mothers. These effects persist throughout the life span, are independent of age and historical period, and can explain fluctuations in homicide arrest rates before the recent upturn.

The Interracial Nature of Violent Crimes: A Reexamination.

Several authors have recently challenged the conception that violent crimes in the United States are disproportionately intraracial. They have posited a special propensity for black offenders to seek out white victims because of black rage and have pointed to the desirable characteristics of white victims. In this paper, three models of the race of offender and victim are developed using aggregate national data on homicide (from the Uniform Crime Reports), rape, aggravated assault, simple assault, and robbery (from the National Crime Surveys.) Whatever measures are used, violent crimes are found to be intraracial to a far greater extent than statistically expected under these models. A structural explanation of these findings is presented.

Measuring the Convergence/Divergence of “Serious Crime” Arrest Rates for Males and Females: 1960–1995

It is now almost a quarter of a century since Adler (1975) and Simon (1975)stimulated a debate about the convergence of crime rates for men andwomen. The ensuing debate generated literally dozens of papers. Given theexistence of a series that now extends from 1960 to 1995, this papersuggests an appropriate way to examine the convergence hypothesis usingtime series techniques. These techniques take into consideration the effectsof the following factors: (a) random “shocks” or“innovations,” (b) the potentially lasting effects of suchinnovations, and (c) the autocorrelation that time series oftenexhibit. Using time series techniques on annual data, we examine trends inthe arrest rates for males and females for six Part I crimes (homicide,robbery, aggravated assault, burglary, larceny, and motor vehicle theft)for the years 1960 through 1995. We test for convergence, divergence, notrend, and a special condition of equilibrium between series calledcointegration.

Cohort Variations and Changes in Age-Specific Suicide Rates over Time: Explaining Variations in Youth Suicide

Dramatic changes in the age distribution of suicide in the U.S. are associated with variations in the demographic characteristics of birth cohorts. Using an age-period-cohort-characteristic model, we show that cohort characteristics theoretically linked to integration and regulation have substantively strong and statistically significant relationships with changes in age-specific suicide rates from 1930 to 1995. Members of relatively large cohorts and of cohorts with higher percentages of nonmarital births are at greater risk for suicide throughout their life spans. These results appear for the total population and for race-sex subgroups, even though the age distributions of suicide differ substantially across these demographic groups. They can account for recent sharp increases in youth suicide, as well as more moderate increases in earlier decades.

Cohort Effects on Suicide Rates: International Variations

Recently, the long observed pattern of a monotonic increase in suicide with age has shifted, often dramatically, because more recent birth cohorts have exhibited much higher suicide rates at younger ages than earlier cohorts have. These changes, however, did not occur in all countries. We examine cohort variations in suicide rates in 14 modern, western societies using an extension of the age-period-cohort characteristic model that incorporates hierarchical linear modeling. Results support a general Durkheimian perspective. Birth cohorts experiencing relatively less social integration and regulation, as measured by higher rates of nonmarital births and larger relative cohort size, have higher suicide rates than other cohorts. Societies that provide alternative sources of social integration and regulation, as through collectivist institutions or through greater support for families and children, moderate this tendency. On the other hand, when societies experience rapid social change, the relationship between decreased social integration and regulation and increased suicide rates is stronger, especially for males. These results have implications for stemming the increased suicide rates for youth observed in many contemporary societies. Language: en

Still Separate and Unequal? A City-Level Analysis of the Black-White Gap in Homicide Arrests since 1960

More than four decades ago, the Kerner Report chronicled the violent disturbances of the 1960s and predicted that the United States was rapidly moving toward two racially separate and unequal societies. Resulting concerns about black and white inequality form a critical chapter in the history of sociological research. Few studies, however, explore trends in racial inequality in rates of violence. Has the gap between black and white violence rates significantly narrowed since 1960 and, if so, why? Drawing on recent work on assimilation and the literature on race inequality, we develop a set of hypotheses about black-white differences in violence rates and how these rates may have changed during the past four decades. We emphasize race differences in family structure, economic and educational inequality, residential integration, illicit drug involvement, and population composition. Using race-specific homicide arrest and census data on social, economic, and demographic conditions for 80 large U.S. cities from 1960 to 2000, we find substantial convergence in black-white homicide arrest rates over time, although this convergence stalled from the 1980s to the 1990s. Consistent with theoretical expectations, we find that, since the 1960s, the racial gap in homicide arrests declined more substantially in cities that had greater reductions in the ratio of black to white single-parent families, as well as in cities that experienced greater population growth and increases in the proportion of the population that is black. Also, as expected, the race gap in homicide arrests widened in cities that had an increasing ratio of black to white rates of drug arrests. Measures of racial integration, however, have no discernible impact on the black to white homicide arrest ratio.

A Mixed Model Estimation of Age, Period, and Cohort Effects

For more than 30 years, sociologists and demographers have struggled to come to terms with the age, period, cohort conundrum: Given the linear dependency between age groups, periods, and cohorts, how can these effects be estimated separately? This article offers a partial solution to this problem. The authors treat cohort effects as random effects and age and period effects as fixed effects in a mixed model. Using this approach, they can (1) assess the amount of variance in the dependent variable that is associated with cohorts while controlling for the age and period dummy variables, (2) model the dependencies that result from the age-period-specific rates for a single cohort being observed multiple times, and (3) assess how much of the variance in observations that is associated with cohorts is explained by differences in the characteristics of cohorts. The authors use empirical data to see how their results compare with other analyses in the literature.

A Common Explanation for the Changing Age Distributions of Suicide and Homicide in the United States, 1930 to 2000

A longstanding debate focuses on whether suicide and homicide rates walk hand in hand or whether they are reciprocally related. Much of the research on this issue investigates whether suicide or homicide predominates in certain geographic areas or whether they trend together over time. We theorize that the degree of social integration and social regulation associated with birth cohorts is negatively related to both of these forms of lethal violence. We develop a common explanation for shifts in the age distributions of homicide and suicide in the United States from 1930 to 2000. In this context, suicide rates and homicide rates walk hand in hand and their parallel movements are associated with two variables linked to social integration and regulation.