What's the easiest way to drop probation violations by 93%?

Cut the severity of punishment, but deliver it immediately:

Alm decided to try something different. He reasoned that if the offenders knew that a probation violation would lead immediately to some certain punishment, they might shape up. “I thought, What did I do when my son was young?” he recalled. “If he misbehaved, I talked to him and warned him, and if he disregarded the warning, I gave him some kind of consequence right away.” Working with U.S. marshals and local police, Alm arranged for a new procedure: if offenders tested positive for drugs or missed an appointment, they would be arrested within hours and most would have a hearing within 72 hours. Those who were found to have violated probation would be quickly sentenced to a short jail term proportionate to the severity of the violation — typically a few days.
Alm mentioned his plan to the public defender, who suggested that it was only fair to warn probationers that the rules were going to be strictly enforced for the first time. Alm agreed, and on Oct. 1, 2004, he held a hearing for 18 sex offenders, followed by another one for 16 drug offenders. Brandishing a laminated “Wanted” poster, he told them: “I can guarantee that everyone in this courtroom wants you to succeed on probation, but you have not been cutting it. From now on, you’re going to follow all the rules of probation, and if you don’t, you’re going to be arrested on the spot and spend some time in jail right away.” He called the program HOPE, for Hawaii’s Opportunity Probation With Enforcement, and prepared himself for a flood of violation hearings.
But they never materialized. There were only three hearings in the first week, two in the second week and none in the third. The HOPE program was so successful that it inspired scholars to evaluate its methods. Within a six-month period, the rate of positive drug tests fell by 93 percent for HOPE probationers, compared with a fall of 14 percent for probationers in a comparison group.