A NEW STUDY by the Rand Corporation makes the point that crime can be significantly reduced if the busiest criminals are given the longest prison sentences. Such offenders could be identified by matching them against seven variables: imprisonment for more than half the two years prior to arrest; a previous conviction for the same crime; a conviction before the age of 16; commitment to a juvenile facility; recent heroin or barbiturate use; drug use as a juvenile, and unemployment for more than half the preceding two years. A criminal is likely to be a high-rate offender if four of these seven characteristics apply to him. The Rand study suggests that if such persons were given long sentences and all other sentences were reduced, crime would be reduced dramatically while the overall prison population would decline.

It was exactly this kind of chronic offender that the D.C. Council hoped to intercept when it enacted amendments to the pretrial detention law in July. The new law focuses on three problems. In the first category are persons who are charged with a violent crime while they are free awaiting trial on another similar offense. Now the prosecutors can ask that they be held for three days while a decision is made on whether to consolidate cases or amend the earlier recommendation for release pending trial. Since the new law went into effect in July, this delay has been granted in 54 cases, and 50 of these defendants are now in custody.

The law was also changed on parolees and probationers who are charged with new crimes. These people were held for five days so that the Parole Board could consider revoking parole or the judge in the initial case could revoke probation. Unfortunately, many new arrests were made on weekends, and in those circumstances five days was not enough time for notification and reconsideration. The new law allows detention for five working days in order to provide enough time in every case. Of such offenders arrested since last July, 21 probationers and 46 parolees are now in custody.

The most controversial part of the new law allows judges to detain persons accused of first-degree murder. These defendants are not always chronic offenders, but if there is doubt that they will appear for trial or fear that they would pose a danger to the community they can be held in custody indefinitely until they are brought to trial. This provision is still being tested in the courts, but last week a three- judge panel of the D.C. Court of Appeals voted to uphold it. Since July, 22 persons have been arrested and charged with first-degree murder; 19 are in custody awaiting trial.

Some of these people, especially those on parole or probation, might have been held under the old law. Indeed, an additional l7 offenders who do not fall into the categories enumerated above were held during this time period under the provisions of the old pretrial detention law requiring a hearing and an expedited trial. But the bottom line is that using the old and the new laws during the last three months, a total of 153 chronic offenders and persons charged with first-degree murder have been held in custody until trial.

U.S. Attorney Stanley S. Harris has said, "The community is fed up with violent crime, fed up with what it perceives to be the recurring situation of someone's being arrested for a violent crime and being back on the street the next morning." These new figures indicate that steps have been taken to change that despairing perception.