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(<i>Completed</i>), those who voluntarily withdrew after six months of EMA data collection (<i>Withdrew</i>), and those unenrolled by staff after six months of poor EMA response rates (<i>Unenrolled</i>). 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 (<i>p</i> < 0.001). Regardless of response rates, μEMA was perceived as less burdensome than EMA (<i>p</i> < 0.001). These results suggest μEMA is a viable method for intensive longitudinal data collection, particularly for participants who find EMA unsustainable.