Ecological Momentary Assessment (Disability)

A standard questionnaire asks people to summarize their experience over a past period, which invites recall bias, peak-end effects, and aggregation that hides variability. EMA instead samples experience repeatedly in the moment and in the person's natural environment, usually through smartphone prompts several times a day for one to several weeks. This yields intensive longitudinal data that capture how disability-relevant states fluctuate and what contexts accompany them, allowing within-person dynamics to be studied rather than a single retrospective estimate.

There are three. Signal-contingent sampling prompts participants at random or scheduled times to characterize ordinary, representative experience. Event-contingent sampling asks for a report whenever a defined event occurs, such as a pain flare, to zoom in on specific occurrences. Interval-contingent sampling collects reports at fixed times to track regular rhythms. Studies often combine schemes — for example, random daytime prompts plus event-contingent flare reports — to balance representativeness, focus on key events, and participant burden, which Stone and Shiffman highlighted as central design choices.

EMA depends on participants responding to prompts on a mobile device, so if the device or interface is not usable by people with visual, motor, cognitive, or other impairments, the method silently excludes the very population it aims to study and biases the sample toward those who can use standard interfaces. Accessible design — adjustable formats, alternative input, screen-reader compatibility, and manageable prompt frequency — is therefore essential. Ensuring the assessment itself is accessible is both an ethical requirement and a validity requirement, because excluded experiences cannot be measured.