Of note was that Project MATCH patients electing to attend AA, irrespective of which treatment they initially received, had significantly better outcomes overall (Tonigan et al, 2003). How AA attendance led to these improvements has become a focus of investigation (e.g., Kelly et al, 2010a; Kelly et al, 2010b; Tonigan et al, 2002), but whether AA's association with better outcomes found in MATCH can be explained by AA's ability to mobilize social process changes has yet to be examined. In the present study, we make use of the large, multisite, sample collected in Project MATCH and employ a prospective design to examine the extent to which AA independently influences four social recovery processes: reductions in high risk social network ties; increases in low risk social network ties; reductions in drinking-related activities; and increases in abstinence-related activities. We conduct lagged meditational tests that yield estimates of the proportion of the direct effect of AA on drinking outcomes that is accounted for by each of these four purported mechanisms. We hypothesize that more frequent AA attendance will be associated with more abstinence
