DECLINING VIOLENT CRIME RATES IN THE 1990S: Predicting Crime Booms and Busts.

INTRODUCTION

Recent declines in rates of violent crime in the United States caught many policymakers and researchers off guard. These declines were perhaps more surprising in that they came on the heels of dire predictions about the rise of a generation of "superpredators" who would soon unleash the full force of their destructive capacities on an already crime-weary nation (Bennett et al 1996, Fox & Pierce 1994).

I argue in this paper that changes such as those involving the recent downturn in violent crime rates usually surprise researchers because we rely mostly on cross-sectional analysis and rarely study social phenomenon like crime trends in a longitudinal context. I begin this article by looking more closely at the recent downturn in violent crime rates, comparing it to trends since World War II. I then summarize and evaluate several common explanations for changing violent crime rates. Finally, I identify a set of concepts that might be useful for moving our thinking about social phenomenon such as crime toward a more longitudinal framework.

Studying Crime Trends in Postwar America

I concentrate here on violent crime trends for the United States. While violent crime generally includes murder, rape, robbery, and aggravated assault, researchers agree that data are probably most accurate for murder and robbery (Gove et al 1985, O'Brien 1996). A focus on the United States is strategic in that it accounts for the greatest volume of research, although such a focus simultaneously underscores the strategic importance of developing more cross-national comparisons.

Researchers interested in studying violent crime trends in the United States are limited to two main data sources: the Uniform Crime Reports (UCR), collected annually since 1930 by the Federal Bureau of Investigation; and the National Crime Victimization Survey (NCVS), collected every six months since 1973 by the Bureau of Justice Statistics (Rand et al 1997). Space limitations prevent a detailed assessment of the strengths and weaknesses of these data sets (Biderman & Lynch 1991, LaFree 1998a:Ch. 2). I concentrate here on the UCR because it provides the longest uninterrupted crime series data for the United States.

Figure 1 shows UCR trends for murder and robbery, 1946 to 1997. I begin the series in 1946 because of serious validity problems with pre-World War II UCR data. I use "longitudinal" throughout this paper to refer to studies based on annual time-series analysis.

My first concern is to identify the major trends in violent crime rates during the post-World War II period. In fact, considering this issue provides insight because it illustrates how little emphasis we have placed on longitudinal changes in crime rates. We lack even a basic shared vocabulary to describe crime changes in precise language. I use the term crime "boom" to refer to a rapid increase in crime rates and crime "bust" to a rapid decline.

Converting the annual rates depicted in Figure 1 to annual percentage changes shows that the longest sustained increases in murder and robbery rates occurred from the early 1960s to the mid-1970s. Taken together, murder rates increased by 113.04% from 1963 to 1974 and robbery rates increased by 222.47% from 1961 to 1971. While rape and aggravated assault rates are generally less reliable, they also increased dramatically during this period; both nearly tripled from the 1960s to the early 1970s. Hence, the most persuasive evidence for a postwar violent crime boom comes from the years about 1961 to 1974. While there were other periods of increase (especially the late 1970s and the late 1980s), none was as steep or as sustained.

Evidence for a single crime bust is less clear. Thus far at least, none of the four violent crimes rates have shown declines that were as long or as steep as the increases of the 1960s and early 1970s. Still, Figure 1 shows that, from 1991 to 1997, murder rates declined in five of six years and robbery rates declined in all six years. In fact, for both murder and robbery, the largest sustained declines of the postwar period have occurred in the 1990s. Murder rates dropped by 30.6% and robbery rates by 31.8% from 1991 to 1997. Rape and aggravated assault rates have also registered declines in the 1990s: rape rates fell by 15.1% and aggravated assault rates by 11.8%.

EXPLAINING POSTWAR VIOLENT CRIME TRENDS

One of the most important justifications for taking a longitudinal approach to crime trends is that it provides insights that are unavailable in cross-sectional designs. With regard to the trends shown in Figure 1, two insights are especially important. First, postwar US violent crime trends sometimes changed very rapidly. In the space of just over ten years in the 1960s and early 1970s, murder rates more than doubled and robbery rates more than tripled. Likewise, in the space of only six years in the 1990s, murder and robbery rates fell by about a third. The simple rapidity of these changes calls into question explanations of crime based on fixed biological characteristics, deep-seated psychological characteristics, or slow-moving social characteristics.

Second, a longitudinal perspective underscores the obvious but often neglected fact that events like the crime boom of the 1960s and the crime bust of the 1990s are situated in distinct historical periods. This fact reminds us of the importance of considering not only what causes crime to increase or decline in general, but more specifically, what particular historical events were directly associated with these changes.

In the sections that follow, I divide common explanations for postwar crime trends into exogenous and public policy effects. I specifically consider how well each explanation fits the timing of the 1960s crime boom and the 1990s crime bust.

Exogenous Effects

I define exogenous effects as those that are largely independent of crime policy. The three exogenous effects that have probably been most frequently linked to violent crime by researchers are economic stress, political legitimacy, and family disorganization. Other exogenous effects with special relevance for crime trends are the proportion of young people, drug markets, and changes in the public's routine activities.

ECONOMIC STRESS The proposition that increased levels of economic stress raise crime rates cuts across otherwise competing models, including theories of social disorganization (Shaw & McKay 1942, Kornhauser 1978), social strain (Merton 1938, Cloward & Ohlin 1960), violent subcultures (Wolfgang 1967, Blau & Blau 1982:118), conflict (Taylor et al 1973, Chambliss 1988), criminal motivation (Cohen et al 1980, Cantor & Land 1985), and macroeconomics (Becker 1968, Brenner 1976). While specific arguments vary enormously, most theorists assume that economic stress undermines legitimacy and weakens social bonds.

Economic stress models of US crime rates work well for the early postwar period when a strong economy was paired with low, stable crime rates. The war jolted the US economy out of a devastating depression, matched the undamaged industrial plants of the United States against the war-torn factories of Europe and Japan, and established America as a supermarket to the world (Levy 1987, Wallerstein 1995). However, connections between economic stress variables and crime trends are less certain for the middle postwar period (from about 1961 to 1973), when rapidly accelerating crime rates were paired with what appeared to be a fairly robust economy. This problem is well expressed by Wilson's (1975:3) influential challenge to researchers to explain "the paradox" of "crime amidst plenty." One possible explanation for this seeming paradox is that crime trends are dependent on specific economic stress measures.

Measures of economic stress can usefully be divided into absolute measures (which refer to how individuals or groups of individuals are doing in comparison to some fixed level of economic well-being) and relative measures (which emphasize how one individual or group of individuals is doing compared to other individuals or groups; LaFree 1998a:119-20). Common absolute measures of economic stress are poverty, median income, and unemployment; common relative measures are income inequality and inflation. Of the two types, relative measures have thus far been more successful at explaining longitudinal crime trends in the postwar United States (Devine et al 1988, LaFree & Drass 1996). While absolute measures of economic stress like unemployment and median income were generally favorable during the middle postwar years, relative measures like income inequality and inflation were far less favorable.

Although it is still too early to tell, economic stress perspectives may also help explain the crime bust of the 1990s. In 1996, the federal spending deficit reached its lowest level since 1979 (US Economic Report to the President 1997). In 1994, the poverty rate began to fall for the first time in five years and income inequality began a modest decline (US Economic Report to the President 1997). In 1997, unemployment reached its lowest level since 1973 (US Economic Report to the President 1997). After reaching double digits in the 1970s and early 1980s, inflation cooled off during the 1990s, remaining under 3% from 1990 to 1996 (US Economic Report to the President 1997).

POLITICAL LEGITIMACY Weber (1947:324) defines legitimate power (or "authority") as "the probability that certain commands (or all commands) from a given source will be obeyed by a given group of persons" and adds that a basic criterion of legitimate power is a "minimum of voluntary submission" (p. 329). All societies face the ongoing problem of legitimizing their rules and laws and transmitting this legitimacy to succeeding generations. Legitimation is the process of explaining and justifying the social rules to new societal members (Berger & Luckmann 1967:93). This reasoning suggests that crime and deviance rates may be related to trends in the legitimacy of political institutions.

Before the mid-1960s, most researchers assumed that challenges to political legitimacy such as protests and riots were directly related to crime rates (Useem …