Pretty well, according to this article.
From the Washington Post Wonkblog:
A watershed in scientist’s views of the value of AA occurred in the 1990s with Project MATCH, the largest study of alcohol dependence treatment ever undertaken. Two well-validated professionally-developed psychotherapies were evaluated head to head against “twelve-step facilitation counselling.” This counselling approach adapted AA ideas and goals into a 3-month long psychotherapist-delivered outpatient treatment protocol and also strongly encouraged involvement in community-based AA groups.
AA skeptics were confident that by putting AA up against the best professional psychotherapies in a highly rigorous study, Project MATCH would prove beyond doubt that the 12-steps were mumbo jumbo. The skeptics were humbled: Twelve-step facilitation was as effective as the best psychotherapies professionals had developed.
Here is the best part: Alcoholics Anonymous is free, and there are meetings near you, at all hours of the day. Here is a link to find a meeting in the Chicago area.