Crime and Punishment in America: 1998

Policy Reports | Crime

No. 219
Thursday, September 24, 1998
by Morgan O. Reynolds

Calculating Expected Punishment

  "Between 1980 and 1996, expected punishment for murder increased from 13 months to 37 months."It is virtually impossible to prevent people outside of prison from committing crimes. Since criminals do not knowingly commit crimes in front of the police, the police rarely catch them in the act. The criminal justice system relies on punishments imposed afterward. In effect, the system constructs a list of prices (expected punishments) for various criminal acts, and criminals decide whether they are willing to pay, just as many of us decide whether to risk parking or speeding tickets.

V  "Expected punishment for rape nearly tripled to 119 days."iewed this way, the expected prison sentences are the prices we charge for various crimes. Thus, the price of murder is three years in prison after we factor in the odds of getting away with it, the price of burglary is about eight days and the price of auto theft is two days.

"Expected punishment for robbery rose by half after 1980 to 52 days in 1996."Expected punishment as a measure of the cost of committing a crime also captures the effectiveness of the criminal justice system in a single number. Expected punishment is not the same as the length of time criminals stay in prison. Rather, expected punishment is calculated by multiplying four probabilities of being arrested for a crime after it is committed, of being prosecuted if arrested, of being convicted if prosecuted and of going to prison if convicted and then multiplying that product by the median time served for an offense.

  • For every 100 burglaries committed, about 50 will be reported to the police.
  • FBI data for 1996 show that about 13.8 percent of reported burglaries will be cleared by arrest, or about 6.9 burglaries out of the 50 reported.
  • The data on tracking offenders [ see Table I ] show that about nine out of every 10 arrests for burglary will be prosecuted, or 6.2 out of 6.9.
  • Two-thirds of the resulting 6.2 prosecutions will result in felony convictions, or 4.2 felony convictions out of every 100 burglaries.
  • Of these convictions, 1.9 felons will be sent to prison while the remaining 2.3 will receive some combination of probation, fines or jail time.

Thus, the overall probability of doing any prison time for committing a burglary is only 1.9 percent.

"Expected punishment for aggravated assault nearly doubled to 13 days in 1996."Once in prison, a burglar will stay there for a median time of about 16 months until release. In 1996, an estimated 1.6 of every 100 burglaries reported to the police resulted in prison time (38,018 court commitments to prison of 2,501,500 reported burglaries), so the median prison term per act of burglary is only 7.7 days (1.6 percent x 16 months x 30 days per month). While this may seem like a short time, it is a sharp increase over the expected punishment of 4.8 days in 1990.

"Expected punishment for burglary doubled between 1980 and 1996."On average then, a potential criminal can expect to spend less than eight days in prison for an act of burglary. This expectation of prison time per crime is, of course, heavily influenced by the chances of getting away with it. However, on the average, a rational, risk-neutral criminal should find burglary profitable so long as what is stolen is worth eight days behind bars.

"The odds of going to prison for a burglary are just over 3 percent."Expected Punishment for Other Crimes. Table I displays the 1996 probabilities of arrest, the 1990 probabilities of prosecution, and the 1994 probabilities of conviction and imprisonment for the other FBI index crimes as well. 17 Multiplying these probabilities together results in probabilities of prison time ranging from 1.4 percent for motor vehicle theft to 40.3 percent for murder. Table II shows how the clearance (that is, the solving) of serious crimes by arrest has declined since 1950. In 1950, for example, 94 percent of murders were cleared by an arrest but only 67 percent of murders in 1996 were (i.e., the chance of getting away with murder rose from 6 percent to 33 percent). Similar declines in arrest clearance ratios occurred for the remaining crimes.

"The clearance of serious crimes by arrest has declined since 1950." Expected punishment for five serious crimes for selected years is shown in Table III . In 1950, expected punishment for murder and nonnegligent manslaughter was 2.3 years. This had dropped to 1.1 years by 1970, but recovered to 3.1 years by 1996. Capital punishment was a more serious concern for murderers in the late 1940s and early 1950s, when over 100 prisoners were executed each year after relatively short stays on death row. This compares to fewer than 40 executions per year in the 1990s after lengthy stays on death row averaging nine or 10 years. In 1950 the chances of a murderer being executed was 1.5 of every 100 murders and in 1996 only 0.25 of every 100 murders, one-sixth of the low risk in 1950.

  "Capital punishment is much less a concern for murderers today than in the early 1950s."Table IV shows the probability of prison time and median months served for the five serious crimes combined. This is perhaps the best overall index of the effectiveness of the criminal justice system, as well as a measure of the threat posed by the system to criminals. The probability of prison declined steeply between 1950 and 1970 and then slowly recovered, yet it is barely half that of 1950. Median months served have recovered to more than two years but still fall short of the 32 months served in 1950. Expected punishment has recovered to more than two-thirds of what it was in 1960 (22 days versus 30 days).

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