What we want is not just less recidivism but fewer people going to prison in the first place. If you're getting paid for lower recidivism rates, you'll want to increase the rate of people going to prison one time, not zero times. It means you might lobby for the kinds of laws that would make that happen or you might bribe judges to get the kind of inmates you want (which might mean people who are possibly innocent or would really be better off with probation or house arrest).