I got a perfect 100% on my Statistics assignment!
(forgive my bragging; it’s just I was such a tool as an undergraduate)

An analysis of Carrots, Sticks, And Broken Windows, Journal of Law & Economics, Volume XLVIII (1), April 2005

In their paper Carrots, Sticks, And Broken Windows, researchers Hope Corman and Naci Mocan attempt to account for significant reductions in serious crime in New York City between the years 1990 through 1999. Conventional wisdom has suggested that the decreases where due to the tough-on-crime policies of Mayor Rudolph Giuliani’s administration; in particular an aggressive approach to low-level crimes, or the “broken windows” policy. Researchers Corman and Mocan argue that crime reduction may have had more to do with economic factors; namely increases in minimum wage and low unemployment (variables which the researchers label “carrots”). The last component of their model are the “sticks”, variables to measure felony arrests, police force size and the number of New York City residents incarcerated. In the end, the researchers conclude that while economic factors are important in explaining reductions in crime, the deterrence measures proved a more effective tool of crime control.

In this study, the researchers wished to gain information about a specific population; namely the total number of criminal offences for New York City. Since it is impractical to gather all information about all crimes in New York City (approximately 50% of all crime goes unreported (Waller, Sansfacon, 2001,[i]), other crimes may be erroneously left out or miscategorized) the researchers took a population sample of seven reported crimes; murder, assault, robbery, burglary, motor vehicle theft, grand larceny and rape. [ii] Again, for practical reasons, the researchers used minimum wage rates and unemployment figures for New York City as a sample of economic indicators.

Overall, this study showed that misdemeanor arrests had the strongest impact on motor vehicle theft, robbery and grand larceny. For example a 10 percent increase in misdemeanor arrests equated to a 1.6 to 2.1 percent decrease in motor vehicle thefts, a 2.5 to 3.2 percent decrease in robberies and a 0.5 to 0.6 decrease in grand larcenies. In addition, the study measured the elasticity of economic and enforcement approaches (Elasticity is a measure of a variable’s responsiveness to changes in other variables). The study showed that robbery and motor vehicle were most elastic (most responsive) to enforcement approaches, while assault and rape were relatively inelastic. The study further showed that economic factors had some impact on murder, robbery and grand larceny, but not as significant an impact as enforcement.. Neither economic factors nor crime deterrence showed any significant impact on assault or rape. These summaries make sense for they show that while low level felonies such as robbery, theft and grand larceny can lead to improvements from relatively simple solutions such as “broken windows” policing, more complex crimes such as assault, rape and murder require more complex solutions that involve addressing social and economic issues.

This study was attempting to address the wider parameter of crime in general in the United States. Yet by the researchers own admission, the study has a hard time applying the success of “broken windows” policing to other jurisdictions. For instance, throughout the 1990s, other American municipalities experienced significant reductions in crime without applying the tough-on-crime policies identified with Mayor Giuliani. For instance, the researchers note that Los Angeles, San Diego and San Francisco witnessed decreases in crime rates by 50 percent, 56 percent and 41 percent respectively, yet these cities experienced a decline in misdemeanor arrests over this time period.

[i] Costs and Benefits of Preventing Crime, Crime Prevention Strategies and Implications, 2001, 229, Boulder: Westview Press.

[ii] The study used the U.S. Department of Justice, Bureau of Justice Statistics, Sourcebook of Criminal Justice Statistics, 2000 (2001).


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