Figure 1.

Study procedures

EMA: Ecological Momentary Assessment

*Following the baseline visit scheduler, participants from the random cluster sample provided names and contact information of 2–3 friends.

Index test: the measurement tool under evaluation (26).

Reference standard test: “the best available method for establishing the presence or absence of the target condition” (25).

TAC monitoring, EMA app data collection, and breathalyzer readings were conducted in parallel.