The CHILL Study was conducted online using an online survey software (formR) and a smartphone app (m-Path). People interested in the CHILL Study first had to register for it by providing informed consent. Thereafter, participants were invited to the four online assessment waves (T0 to T3) occurring every 7 weeks. Between T1 and T2, the intervention phase of the CHILL Study took place. During the intervention phase, participants used the app m-Path to answer experience sampling and daily diary questionnaires. Furthermore, participants regularly received intervention prompts depending on their treatment group. Finally, we assessed objective environmental characteristics using mobile sensing methods.
