The notion that a majority of those in prison are petty, first-time offenders with few previous arrests, no previous convictions and no history of violence has been promulgated in many places, but it is completely false.

In state prisons, which hold more than 90 percent of all prisoners, as of 1991, the latest year for which full statistics are available:

• Only 6 percent of prisoners were nonviolent offenders who had not previously been sentenced to probation or incarceration.

• Nearly half were serving time for a violent crime, and one-third had been convicted in the past of one or more other violent crimes.

• Two-thirds of violent inmates had killed, raped or injured their victims.

The federal prison system holds more property and drug offenders and fewer violent offenders than the state prisons. Even there, however:

• Of 35,000 persons newly imprisoned in 1991, only 2 percent, or about 700, were convicted of mere drug possession.

• As of 1989, over 55 percent of all federal prisoners had two or more prior felony convictions.

This shows that most prisoners are indeed violent or repeat criminals. But even these data understate the actual number and severity of crimes committed by prisoners.

• Many of the prisoners have committed violent offenses as juveniles which do not show on their records.

• Prisoners' records do not reflect plea bargaining of more serious crimes to the lesser offenses for which they were sentenced.

• The data do not account for undetected and unpunished crimes the prisoners committed when they were free.

Two recent prisoner self-report surveys suggest that, as bad as the official adult records of most prisoners are, their true adult records are much worse.

• A random sample survey of Wisconsin prisoners in 1990 found that, in the year prior to imprisonment, prisoners committed a median of 12 property or violent crimes, and a mean of 141 such crimes, excluding all drug crimes.

• A similar survey of New Jersey prisoners in 1993 found that, in the year prior to imprisonment, prisoners committed a median of 12 property or violent crimes, and a mean of 220 such crimes, excluding all drug crimes.

In 1991, criminals across the country actually served an average of about 35 percent of their sentence before being paroled. The median time served for murder was 6.5 years on a 20-year sentence and the median time served for assault was 15 months on a four-plus-year sentence.

Source: Adapted from John J. Dilulio, Jr., "The Question of Black Crime," The Public Interest, No. 117, Fall 1994.