Generalizability
SHOCKS, RECRUITMENT
The recruitment period was from January 2 to April 1, 2020, which began with a typical surge in downloads in the new year and ended during the United Kingdom’s first COVID-19 lockdown. Such exogenous shocks to the users’ overall environment during the trial are likely to influence the underlying thoughts, emotions, and behaviors of reducing drinking levels (ie, people were mainly housebound) [