How do you determine whether a prisoner coming up for parole will commit another crime and be put back in jail? The risk of recidivism, the repeated relapse into criminal activity, is one the United States Parole Commission must continually deal with. And perhaps for that reason, the commission has turned to an apparently simple actuarial device -- called a "salient factor score" -- to facilitate the otherwise complex determination.

Currently, answers to seven questions produce a salient factor score, ranging from 0 to 11, for each prisoner seeking parole. The higher the score, the better the chance that the prisoner will not end up in the slammer again.

However, the Dec. 10 Federal Register (page 81212) carried proposed rules setting up new salient factor questions, which differ from the current ones in four specific instances.

Two salient factor questions would be dropped, one on past employment and another on whether the offender had been involved in vehicle thefts or bad checks. "Employment history," the commission notice reported, "has proved quite difficult to score reliably."

Two questions would be revised to focus "somewhat greater emphasis on [the prisoner's] recent criminal record." For example, the question that now asks about "age at first commitment" would be changed to "age at current offense"; and the one asking whether the prisoner has been a "parole violator any time" would be changed to "probation/parole/custody/escape status" at the time of "his current offense."

A new question would be added, seeking to reward the prisoner's "commitment-free period" -- his time out of jail.

The proposed six questions and the point score they carry are laid out.

Prior convictions? None gets you 3 points, one gets you 2; two or three gets 1, and four or more, 0.

Prior commitments (to jail) of more than 30 days? None, 2 points; one or two, 1; and three or more, 0.

Commitment-free period? First imprisonment or "released from last more than 24 months prior to current offense" gets 1 point; otherwise, 0.

Age at current offense? Twenty-eight years old or more is 2 points; 22-27 is 1; 21 or under, 0.

Status at time of current crime? Not on probation, parole, in custody or escape status gets 1 point; otherwise, 0.

Drug dependence? No history of heroin or "opiate dependence" is 1 point; otherwise, 0.

Using the revised questions, a score of 8 to 10 points makes a prisoner a "very good risk" not to repeat his or her criminal behavior; 6 to 7 is a "good risk;" 4 to 5, a "fair risk;" and 0 to 3, a "poor risk." A high score doesn't necessarily guarantee a parole, but it will help.