Do Alcoholics Anonymous participants do better at abstinence than nonparticipants because they are more motivated? Or is it because of something inherent in the A.A. program?
How researchers answered these questions in a recent study offers insight into challenges of evidence-based medicine and evidence-informed policy.
The study, published in the journal Alcoholism: Clinical and Experimental Research, teased apart a treatment effect (improvement due to A.A. itself) and a selection effect (driven by the type of people who seek help). The investigators found that there is a genuine A.A. treatment effect. Going to an additional two A.A. meetings per week produced at least three more days of alcohol abstinence per month.
Separating treatment from selection effects is a longstanding problem in social and medical science. Their entanglement is one of the fundamental ways in which evidence of correlation fails to be a sign of causation. For many years, researchers and clinicians have debated whether the association of A.A. with greater abstinence was caused by treatment or a correlation that arises from the type of people who seek it.
[For more of this story, written by Austin Frakt, go to http://www.nytimes.com/2015/04...2&abg=0&_r=0]
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