The App “Rhythm” automatically recorded smartphone behaviors, mainly the notifications, screen-on and screen-off timing. This App collects data in the background without interrupting smartphone operation or impacting battery life (less than 1%). The App saves all recorded behavior data in a log file and routinely uploaded to the database.
Our previous study has preliminarily validated the consistency between App-recorded and self-reported sleep time. The overlap of total sleep time between App-record and self-reported was 90.4%.