Ecological momentary assessment (EMA, or experience sampling) is a method that has unique advantages., compared to traditional methods using surveys and/or observing people in the laboratory. In the influential paper named on the subject, Saul Shiffman, Arthur Stone, and Michael Hufford discuss categories of ways EMA can be used. These categories include enabling a researcher to study individual differences, contextual associations, natural history, and temporal sequences.
The responses of individuals can be aggregated to get a measurement for each person.
“As estimates of subject characteristics, aggregated EMA data are expected to provide assessments of individuals that are more reliable (because of aggregation) and more valid (because of avoidance of recall bias, representative sampling, and ecological validity).”
An example would be a patient’s average pain, or average pain before and after a medication.
EMA can be used to study an individual’s patterns over time. An example provided was of smoking withdrawal symptoms changed over time in people who recently quit smoking. The study found that “some symptoms peaked immediately when smokers quit and then decreased over time, while others increased and persisted, and still others increased only gradually over time.”
EMA can show relationship between events that happen together or close to one another in real time. In one study, it was used to show that in a moment, one could experience positive or negative emotion, but not both.
Because data for EMA is collected repeatedly over time, one can see the how a sequence of events unfolds over time. Further, one can see events that happen before and after an event of interest, or observe a “cascade” – how events play out. A study sought to confirm a theory that posited that people who lapsed – smoked a cigarette – experienced decreased self-efficacy and increased negative affect after doing so. Further, the study also predicted that decreased self-efficacy and increased negative affect would lead to future lapses – and eventual relapse into smoking. EMA confirmed the first part of the theory- people experienced decreased self-efficacy and increased negative affect- but shed new light on the second part of the theory in that it showed these states/emotions in fact did not predict a slippery slope into relapse.
Ecological momentary assessment can be a useful tool in studying people in real life because it gets uniquely useful data. This data includes reliable, valid data for individuals, showing trends of events or behavior over time, how events co-occur, and how events or behaviors that happen in a certain sequence can influence each other. Fortunately, this unique and useful method can help us learn about ourselves in unique and useful ways.
Shiffman, S., Stone, A. A., & Hufford, M. R. (2008). Ecological momentary assessment. Annu. Rev. Clin. Psychol., 4, 1-32.