Findings in Context
EMA
The finding that neither offering greater reward amounts nor reducing the schedule length led to an increase in the response rate is broadly consistent with systematic reviews of factors associated with EMA compliance [Rewards were selected as the first intervention target as the rewards available in burst 1 were low compared with other studies; participants could receive a total of approximately US $5 for completing all the EMA surveys. In other studies with a similar number of EMA days (between 10 and 14 d) and surveys (between 35 and 50 surveys), the lowest incentive was approximately US $25 [In our study, contrary to our expectations, the burst 2 response rate was significantly higher in the 14-day schedule group than in the shorter 7-day schedule group. It seems intuitive that fewer days of EMA surveys would be less intrusive and therefore preferable to participants, particularly in the context of repeated bursts of EMA surveys. However, our findings indicate the opposite. More research is needed in this area as systematic reviews currently report inconsistent relationships between EMA schedule length and response rate [Although the average response rate in EMA studies has been reported to be >70% [