The Prices We Charge for Crime

Viewed this way, the expected prison sentences are the prices we charge for various crimes. Thus, the price of murder is about two to three years in prison after we factor in the odds of getting away with it, the price of burglary is about six days and the price of auto theft is no more than two days. "The negative correlation between expected punishment and the murder rate is weakest among serious crimes."

"Correlation analysis suggests that a one-week increase in expected punishment reduces rape by 6 percent."

The Solution: Increase Expected Punishment

• increase the proportion of reported robberies cleared by arrest from 23 to 70 percent,
• increase the proportion of the accused that are prosecuted, convicted and imprisoned from 26 to 78 percent or
• increase the median prison time served by robbers from 26 to 78 months.

All three are expensive in the short run. A higher arrest rate requires more money for police staffing, equipment and procedures. Higher conviction and sentencing rates require more resources for prosecution and criminal courts. All three require more prison space for robbers. But a tough approach pays, especially over the long run. As the odds worsen for criminals, crimes decline and the same numbers of arrests and convictions begin to reduce the odds favoring criminals.

Figures IV (9k) to VIII show the relationship between each index crime of violence or burglary and its respective expected punishment since 1950 [see Table IV (9k)]. While not perfect, the correlation between the amount of each crime and its expected punishment is clearly negative.

Statistically, a simple correlation between two variables may range from +1.0 to -1.0, indicating that crime and expected punishment go up and down together perfectly (+1.0) or go up and down in a pattern perfectly opposite from each other (-1.0) or somewhere in between. The simple correlation between each crime and its respective expected punishment is -.26 for murder, -.68 for rape, -.63 for aggravated assault, -.87 for robbery and -.88 for burglary. While all are negative and therefore consistent with the theory that punishment deters, the correlations are most significant for robbery and burglary, increasing our confidence that crimes with an obvious economic motive are particularly sensitive to expected punishment.

"An additional police officer stops eight to 10 serious crimes per year."

Most studies find that criminals and potential criminals are more responsive to changes in arrest and conviction rates than to punishment length. That may be because changes in the first two deterrents are more visible. A clear example of how deterrence works was the response of college basketball players to adding a third referee on the court. Critics feared that the game would be slowed down by more whistles and foul shots, but the number of fouls per game actually fell by 17, a 34 percent reduction. Like criminals, basketball players reduced their infractions in response to more "police" and higher detection rates.20 Similarly, Steven Levitt has shown that an additional police officer stops eight to 10 serious crimes per year.21