Reflections on Declining Crime in Chicago: Executive Summary
This report examines recent crime trends in Chicago. It describes what happened in the city, and
addresses the issue of why crime has declined so precipitously. The report draws upon the conclusions of
research on the drop in crime and data from Chicago for the 14-year period 1991-2005. The conclusions
challenge some popular explanations for declining crime – for example, that it was due largely to growing
prison populations, an increase in the number of police, or the city’s improving economic fortunes. However,
in many instances there is not enough information to adequately test potentially important explanations for
the decline of crime in Chicago. Where appropriate, I have therefore added my own judgment about these
matters to the mix of data and research, and in the conclusion I advance a scenario which might account for
the post-1991 drop in crime in Chicago.
Crime peaked in Chicago in 1991, then began its long decline. By 2005, violent crime declined by 59
percent. The largest decline was in robbery, which went down by 64 percent. Homicide dropped by 52
percent and aggravated assault by 54 percent. Combining all offenses in which a firearm was used in some
way, there was a 64 percent drop in the level of gun crime in Chicago. In the property-crime category, auto
theft and burglary were both down by 52 percent. An important feature of the decline in crime in Chicago is
that it has been extremely widespread. Across the city’s 279 police beats, property crime went up in five and
down in 274 beats, while violent crime went up in 16 beats and declined in 263 beats. Crime declined most
dramatically in predominately African-American communities. For example, gun crime dropped by 65
percent in predominantly African-American areas, and it was also down by 60 percent in heavily Latino
beats. By the mid-2000s, Chicagoans in most neighborhoods had seen tremendous improvement in the
quality of their lives. In a “what if” world in which crime had not dropped, but had instead remained at its
1991 level, by the end of 2005 an additional 3,100 people would have been murdered. There would have
been 16,000 more sexual assaults, 250,000 more burglaries, and 222,000 more auto thefts, if crime had
not dropped as it did.
But why did crime drop so precipitously? There has been a great deal of debate about this question, for
Chicago was not the only city experiencing a substantial drop in crime during the same period. Explanations
for the decline in crime range from “a” (alcohol use, which is down) to “z” (zero tolerance policing). Sections
of the report examine most of the serious claims, matching them up against trends in Chicago. They
conclude that:
• The decline in crime was not due to demographic changes, nor to improving economic conditions for
families or young people.
• Not much of the decline in crime could be attributed to prisons. Trends in incarceration cannot explain
the magnitude of crime decline during the 1990s; crime continued to drop after Illinois’ prisons stopped
growing after 2001; and after 1999 Chicago’s incarceration rate declined along with its crime rate.
• The decline in crime was not due to the deterrent effects of going to jail. The Cook County jail also
expanded during the 1990s – and for several years after prisons stopped growing – but not enough in light
of the probably limited deterrent impact of short spells behind bars.
• Not much of the decline in crime could be attributed to the sheer number of police officers. Police are
expensive, and their numbers did not grow fast enough or long enough.
• Declining crime was not due to the decreased frequency with which Chicagoans carry guns; non-gun
crime declined just as fast and far.
• The decline in crime was not linked to any reduction in the influence of the city’s large and violent
street gangs. Non-gang crime declined consistently, while gang crime traced an up and down course in
response to volatile intra-gang dynamics and a shifting business environment.
• The decline in crime was not due to a declining crack cocaine market. Cocaine-related arrests went
up rather than down, while emergency-room treatment for cocaine-related episodes were as frequent in
2005 as they were in 1991. Except for powder cocaine, drug markets continued to flourish even as crime
dropped. Homicide associated with the drug trade went up and down, but it was a very small proportion of
all violence and it was non-drug violence that dropped consistently.
• Crime did not drop city-wide because of the demolition of public housing. Crime rates in and around
public housing properties dropped faster than they did in the remainder of the city. Those rates always
constituted a small percentage of all crime in the city, however, and could not account for its sweeping
downturn.
• Improving security in the schools could not explain the city-wide decline in crime. School-based
assault did not decline; rather, it skyrocketed in the 2000s. By 2005, aggravated assault in and around
schools made up almost 11 percent of the city’s total. Other kinds of school crime – which are down –
constitute just a small percentage of the city total, and could not account for the dramatic decline in crime.
• While there is evidence that “smarter” policing impacts crime, there is no evidence that police in
Chicago “got smarter” at a pace matching the decline in crime. Any effects of community policing could not
have been felt until the second half of the 1990s, and the police department’s information-driven
crackdowns on drugs and guns did not begin until the 2000s.
• Strengthening community factors were linked to more rapid declines in beat-level crime, but it has not
been clearly demonstrated that, over all, enough communities in Chicago have grown strong enough to
account for generally declining crime. Decades of criminological research have established the importance
of community factors such as the strength of family controls, the depth of informal bonds among neighbors,
and the organized crime prevention efforts of neighborhood groups. But little is known about whether these
factors grew stronger or weaker during the 1990s and 2000s, nor how they might have been affected by
community policing.
The report also reviews claims about the decline in crime for which there are little or no data for
Chicago. These include alcohol consumption, which has been on a nationwide decline at the same time
that violent crime has subsided; the impact of abortion policies on child welfare; “tipping points”; and cultural
shifts. There is evidence of a quickening pace of neighborhood economic vitality during the 1990s and
2000s, but it is unclear is whether this is a cause or a consequence of the drop in crime.
It is most plausible that the roots of the crime drop in Chicago lie in a mix of the factors described here.
Some or many of them may have been working in concert to reduce crime, each contributing something to
the end result. It is also quite possible that the effects of these factors may have waxed and waned in
significance over this substantial period of time. Some may have contributed to the drop in crime early on,
and others later. As the length of the great post-1991 decline in crime extends, it is likely that combinations
and reinforcing mixes of factors are at work, rather than One Big Thing. The paper describes one plausible
crime-drop scenario for Chicago that involves a mix of law enforcement and community factors. The leap in
incarceration rates during the early 1990s could have played a role in crime decline, if prison had larger-
than-average effects during it’s early expansion. The effects of community mobilization around community
policing could have been felt by the latter half of the 1990s, while the police department became visibly
“smarter” and well managed early in the 2000s. The report concludes with a brief discussion of the
comparative costs of interventions designed to further the drop in crime, a necessary component of any
comprehensive policy review.
This report examines recent crime trends in Chicago. It describes what happened in the city, and
addresses the issue of why crime has declined so precipitously. The report draws upon the conclusions of
research on the drop in crime and data from Chicago for the 14-year period 1991-2005. The conclusions
challenge some popular explanations for declining crime – for example, that it was due largely to growing
prison populations, an increase in the number of police, or the city’s improving economic fortunes. However,
in many instances there is not enough information to adequately test potentially important explanations for
the decline of crime in Chicago. Where appropriate, I have therefore added my own judgment about these
matters to the mix of data and research, and in the conclusion I advance a scenario which might account for
the post-1991 drop in crime in Chicago.
Crime peaked in Chicago in 1991, then began its long decline. By 2005, violent crime declined by 59
percent. The largest decline was in robbery, which went down by 64 percent. Homicide dropped by 52
percent and aggravated assault by 54 percent. Combining all offenses in which a firearm was used in some
way, there was a 64 percent drop in the level of gun crime in Chicago. In the property-crime category, auto
theft and burglary were both down by 52 percent. An important feature of the decline in crime in Chicago is
that it has been extremely widespread. Across the city’s 279 police beats, property crime went up in five and
down in 274 beats, while violent crime went up in 16 beats and declined in 263 beats. Crime declined most
dramatically in predominately African-American communities. For example, gun crime dropped by 65
percent in predominantly African-American areas, and it was also down by 60 percent in heavily Latino
beats. By the mid-2000s, Chicagoans in most neighborhoods had seen tremendous improvement in the
quality of their lives. In a “what if” world in which crime had not dropped, but had instead remained at its
1991 level, by the end of 2005 an additional 3,100 people would have been murdered. There would have
been 16,000 more sexual assaults, 250,000 more burglaries, and 222,000 more auto thefts, if crime had
not dropped as it did.
But why did crime drop so precipitously? There has been a great deal of debate about this question, for
Chicago was not the only city experiencing a substantial drop in crime during the same period. Explanations
for the decline in crime range from “a” (alcohol use, which is down) to “z” (zero tolerance policing). Sections
of the report examine most of the serious claims, matching them up against trends in Chicago. They
conclude that:
• The decline in crime was not due to demographic changes, nor to improving economic conditions for
families or young people.
• Not much of the decline in crime could be attributed to prisons. Trends in incarceration cannot explain
the magnitude of crime decline during the 1990s; crime continued to drop after Illinois’ prisons stopped
growing after 2001; and after 1999 Chicago’s incarceration rate declined along with its crime rate.
• The decline in crime was not due to the deterrent effects of going to jail. The Cook County jail also
expanded during the 1990s – and for several years after prisons stopped growing – but not enough in light
of the probably limited deterrent impact of short spells behind bars.
• Not much of the decline in crime could be attributed to the sheer number of police officers. Police are
expensive, and their numbers did not grow fast enough or long enough.
• Declining crime was not due to the decreased frequency with which Chicagoans carry guns; non-gun
crime declined just as fast and far.
• The decline in crime was not linked to any reduction in the influence of the city’s large and violent
street gangs. Non-gang crime declined consistently, while gang crime traced an up and down course in
response to volatile intra-gang dynamics and a shifting business environment.
• The decline in crime was not due to a declining crack cocaine market. Cocaine-related arrests went
up rather than down, while emergency-room treatment for cocaine-related episodes were as frequent in
2005 as they were in 1991. Except for powder cocaine, drug markets continued to flourish even as crime
dropped. Homicide associated with the drug trade went up and down, but it was a very small proportion of
all violence and it was non-drug violence that dropped consistently.
• Crime did not drop city-wide because of the demolition of public housing. Crime rates in and around
public housing properties dropped faster than they did in the remainder of the city. Those rates always
constituted a small percentage of all crime in the city, however, and could not account for its sweeping
downturn.
• Improving security in the schools could not explain the city-wide decline in crime. School-based
assault did not decline; rather, it skyrocketed in the 2000s. By 2005, aggravated assault in and around
schools made up almost 11 percent of the city’s total. Other kinds of school crime – which are down –
constitute just a small percentage of the city total, and could not account for the dramatic decline in crime.
• While there is evidence that “smarter” policing impacts crime, there is no evidence that police in
Chicago “got smarter” at a pace matching the decline in crime. Any effects of community policing could not
have been felt until the second half of the 1990s, and the police department’s information-driven
crackdowns on drugs and guns did not begin until the 2000s.
• Strengthening community factors were linked to more rapid declines in beat-level crime, but it has not
been clearly demonstrated that, over all, enough communities in Chicago have grown strong enough to
account for generally declining crime. Decades of criminological research have established the importance
of community factors such as the strength of family controls, the depth of informal bonds among neighbors,
and the organized crime prevention efforts of neighborhood groups. But little is known about whether these
factors grew stronger or weaker during the 1990s and 2000s, nor how they might have been affected by
community policing.
The report also reviews claims about the decline in crime for which there are little or no data for
Chicago. These include alcohol consumption, which has been on a nationwide decline at the same time
that violent crime has subsided; the impact of abortion policies on child welfare; “tipping points”; and cultural
shifts. There is evidence of a quickening pace of neighborhood economic vitality during the 1990s and
2000s, but it is unclear is whether this is a cause or a consequence of the drop in crime.
It is most plausible that the roots of the crime drop in Chicago lie in a mix of the factors described here.
Some or many of them may have been working in concert to reduce crime, each contributing something to
the end result. It is also quite possible that the effects of these factors may have waxed and waned in
significance over this substantial period of time. Some may have contributed to the drop in crime early on,
and others later. As the length of the great post-1991 decline in crime extends, it is likely that combinations
and reinforcing mixes of factors are at work, rather than One Big Thing. The paper describes one plausible
crime-drop scenario for Chicago that involves a mix of law enforcement and community factors. The leap in
incarceration rates during the early 1990s could have played a role in crime decline, if prison had larger-
than-average effects during it’s early expansion. The effects of community mobilization around community
policing could have been felt by the latter half of the 1990s, while the police department became visibly
“smarter” and well managed early in the 2000s. The report concludes with a brief discussion of the
comparative costs of interventions designed to further the drop in crime, a necessary component of any
comprehensive policy review.
Work in Progress
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