Communities mobilizing for change on alcohol (CMCA): effects of a randomized trial on arrests and traffic crashes

We previously reported effects of the CMCA intervention in reducing social and commercial access to alcohol by youth, and reducing alcohol use by 18-20-year-olds. This paper reports on effects of CMCA on arrests and car crashes.

CMCA was a group-randomized trial that implemented and evaluated a community-organizing effort to change community policies and practices to reduce youth access to alcohol. Seven Midwestern communities were randomly assigned to the intervention condition and eight communities were assigned to the control condition.

For 2.5 years, a part-time community organizer worked in each of the seven intervention communities with local public officials, enforcement agencies, alcohol merchants, the media, schools and other community groups to reduce youth access to alcohol.

We collected annual arrest and quarterly traffic crash data for the years 1987-1995, providing a 6-year baseline and 3 years of data during the intervention. Data were stratified into two target age groups (15-17 and 18-20) and a control group (age 21 and over). Analyses used random-coefficient models because we had repeated observations for each unit of assignment in a group-randomized trial with heterogeneous trends across communities.

We observed net declines in the intervention communities for all arrest and traffic crash indicators. The decline was statistically significant for DUI arrests among 18-20-year-olds and approached significance for DUI arrests and disorderly conduct violations among 15-17-year-olds.

Together with previously published results from this study, the results reported here suggest that a community-organizing approach to limit youth access to alcohol may be effective, at least for selected end-points and subgroups. We conclude that this approach may be useful, but that a longer intervention period is required to increase effectiveness.