“Our goal at CODA is to create a system of care that uses evidence-based practices at just the right dose and just the right time,” Mr. Hartnett said. “As with many chronic diseases, figuring out dosage and timing are critical.”

For some addicts, a standard program may not help at all, according to Anne Fletcher, who for her book “Sober For Good” interviewed 222 men and women who had been clean for at least five years. “A lot of these people overcame an alcohol problem on their own, or with the help of an individual therapist,” Ms. Fletcher said.

To complicate matters in Oregon, the state mandate has stirred a kind of culture clash between those who want reform — academic researchers, state officials — and veteran counselors working in the trenches, many of whom have beaten addictions of their own and do not appreciate outsiders telling them how to do their jobs.

“I’m a counselor, and I’d be defensive, too: ‘What do you mean, all this stuff I’ve been doing my entire life is wrong?’ ” said Brian Serna, director of outpatient services at Adapt, who has traveled the state to monitor the use of scientific practices. “So the challenge is to build a bridge between what the science says is effective and what people are already doing.”

One way to do that, some experts now believe, is to combine evidence-based practice with “practice-based evidence” — the results that programs and counselors themselves can document, based on their own work. In 2001 the Delaware Division of Substance Abuse and Mental Health began giving treatment programs incentives, or bonuses, if they met certain benchmarks. The clinics could earn a bonus of up to 5 percent, for instance, if they kept a high percentage of addicts coming in at least weekly and ensured that those clients met their own goals, as measured both by clean urine tests and how well they functioned in everyday life, in school, at work, at home.

By 2006, the state’s rehabilitation programs were operating at 95 percent capacity, up from 50 percent in 2001; and 70 percent of patients were attending regular treatment sessions, up from 53 percent, according to an analysis of the policy published last summer in the journal Health Policy.

“We basically gave them a list of evidence-based practices and told them to pick the ones they wanted to use,” said Jack Kemp, former director of substance abuse services for Delaware, in an interview. “It was up to them to decide what to use.”

For those who are trying not to use, it doesn’t much matter how rehab services are improved — only that it happens in time. “Honestly, you just don’t care how or why something works for you,” said Ms. Hatton, the 25-year-old from Myrtle Creek, Ore. “Just that it does.”