Crime and Punishment in America: 1999

Studies | Crime

No. 229
Friday, October 01, 1999
by Morgan O. Reynolds


Why the Serious Crime Rate Has Fallen

Figure II - Murder and Expected Prison Time%2C 1950-1998

Most offenders are not deranged. And most crimes are not irrational. Instead, criminal acts are freely committed by people who often compare the expected benefits to the expected costs.11 The reason we have so much crime is that, for many people, the benefits outweigh the costs.12 But in recent years the likelihood of going to prison for committing any type of major crime has increased, as has the amount of prison time served. In 1997 alone (the latest year for which prison data are available), the probability of going to prison for murder rose 13 percent from 1996, for rape 1 percent, for robbery 7 percent and for aggravated assault 11 percent; the probability of going to prison for burglary remained the same. In addition, wages have gone up and unemployment has gone down. In response to these developments, people are committing fewer crimes. Since 1993:13

  • The murder rate has dropped 34 percent, as the probability of going to prison for murder has risen 54 percent.
  • Rape has decreased 17 percent, as the probability of prison has increased 20 percent.
  • Robbery has decreased 35 percent, as the probability of prison has increased 24 percent.
  • Aggravated assault has decreased 18 percent, as the probability of prison has increased 26 percent.
  • Burglary has decreased 22 percent, as the probability of prison has increased 21 percent.

Moreover, once in prison criminals are staying longer. Compared to the 1980s, the median sentence served by prisoners released in the 1990s has risen for every category of serious crime except aggravated assault.

Figure III - Rape and Expected Prison Time%2C 1950-1998

"The likelihood of going to prison for a crime has increased, as has the length of time likely to be spent there."

The best overall measure of the potential cost to a criminal of committing crimes is "expected punishment." Roughly speaking, expected punishment is the number of days in prison a criminal can expect to serve per crime, given the probabilities of being apprehended, prosecuted, convicted and going to prison, and the median months served for each crime. In 1997 expected punishment for murder increased 13.3 percent over 1996, for rape 2.4 percent, for robbery 13.5 percent and for aggravated assault 20 percent; there was no change in expected punishment for burglary. Between 1980 and 1997, expected punishment:

  • for murder nearly tripled from 14 months to 41 months.
  • for rape tripled to 128 days.
  • for robbery increased by 70 percent to 59 days.
  • for serious assault more than doubled to 18 days.
  • for burglary more than doubled from 4 days to 9 days.

Evidence shows that potential criminals respond to incentives. Crime increases when expected punishment declines, and vice versa. Between 1950 and 1980, expected punishment for crimes of violence and burglary declined more or less continuously from an average of seven weeks for every serious crime committed to only 10 days - an 80 percent drop. In response, the serious crime rate more than quadrupled during those years. In the 1980s, expected punishment began to increase, accompanied by the leveling off and then a decline in the serious crime rate. Between 1980 and 1997, expected punishment for serious crimes more than doubled, increasing from 10 to 25 prison days. Over the same period, the crime rate fell nearly 40 percent.

Figure IV - Robbery and Expected Prison Time%2C 1950-1998

Figures II to VI [II, III, IV, V, VI] show the relationship between each type of violent crime and burglary and its respective expected punishment since 1950. While far from perfect, the negative association between the amount of each crime and its expected punishment is apparent.14

Figure V - Aggravated Assault and Expected Prison Time%2C 1950-1998Figure VI - Burglary and Expected Prison Time%2C 1950-1998

Read Article as PDF