An experimental evaluation of assessment reactivity in ecological momentary assessment of alcoholics anonymous involvement and alcohol-related outcomes: One day at a time.

OBJECTIVE: Assessment reactivity refers to the extent to which repeated measurement of behavioral and psychological phenomena influences subsequent behavior change. The present study used ecological momentary assessment (EMA) to evaluate whether frequent self-report influences Alcoholics Anonymous (AA)-related processes and alcohol-related outcomes. METHOD: = 59), completing only baseline and 3- and 6-month follow-up assessments. Mean differences were examined using t tests, covariance comparisons using multigroup path analysis, and longitudinal trajectory differences using linear mixed-effects models. RESULTS: Across 30 mean and 210 covariance comparisons, only one mean difference (spiritual step work) and seven covariance differences were statistically significant between groups, a pattern consistent with chance variation (<5% of differences expected by chance). No significant group or group-by-time effects emerged for key behavioral outcomes, including proportion days abstinent, AA meeting attendance, or drinks per drinking day. CONCLUSIONS: Despite frequent assessments over a uniquely long EMA sampling period (6 months), EMA participation was not associated with systematic changes in alcohol use, AA involvement, or related mechanisms. These findings suggest little evidence that EMA procedures meaningfully influence the processes they are intended to measure (i.e., limited evidence of assessment reactivity) in the context of the present study. (PsycInfo Database Record (c) 2026 APA, all rights reserved).