Longitudinal User Engagement with Microinteraction Ecological Momentary Assessment (μEMA)

Microinteraction ecological momentary assessment (μEMA) is a type of EMA that uses single-question prompts on a smartwatch to collect real-world self-reports. Smaller-scale studies show that μEMA yields higher response rates than EMA for up to 4 weeks. In this paper, we evaluated μEMA's longitudinal engagement in a 12-month study. Each participant completed EMA surveys (one smartphone prompt/hour for 96 days in 4-day bursts) and μEMA surveys (four smartwatch prompts/hour for the 270 days). Using data from 177 participants (1.37 million μEMA and 14.9K EMA surveys), we compared engagement across three groups: those who completed 12 months of EMA data collection(Completed), those who voluntarily withdrew after six months of EMA data collection (Withdrew), and those unenrolled by staff after six months of poor EMA response rates (Unenrolled). Compared to EMA, unenrolled participants were 2.25 times, those who withdrew were 1.65 times, and completed participants were 1.53 times more likely to answer μEMA prompts (p < 0.001). Regardless of response rates, |μEMA was perceived as less burdensome than EMA (p < 0.001). These results suggest μEMA is a viable method for intensive longitudinal data collection, particularly for participants who find EMA unsustainable.