JMIR Publications

ABSTRACT

Background:

Ecological momentary assessment (EMA) is an in-situ method of gathering self-report on behaviors using mobile devices. Microinteraction-EMA (Micro-EMA or μEMA) is a type of EMA where all the self-report prompts are single-question surveys that can be answered using a one-tap glanceable microinteraction, conveniently on a smartwatch. Prior work suggests that μEMA may permit a substantially higher prompting rate than EMA with higher response rates. However, the validity of μEMA self-report has not yet been assessed.

Objective:

In this pilot study, we evaluated the criterion validity of μEMA on a smartwatch, using physical activity (PA) assessment as an example behavior of interest.

Methods:

Seventeen participants answered 72 μEMA prompts each day for one-week, self-reporting whether they were doing sedentary, light/standing, moderate/walking, or vigorous activities at each prompt. Responses were then compared with a research-grade activity monitor worn on the dominant ankle continuously measuring PA.

Results:

We observed significantly higher (P <.001) momentary PA levels on the activity monitor when participants self-reported (using μEMA) engaging in moderate/walking or vigorous activities as compared to sedentary or light/standing activities.

Conclusions:

For PA measurement, high-frequency μEMA self-report could be used to capture the information comparable to that of a research-grade continuous sensor – suggesting criterion validity.