Ecological Momentary Assessment Techniques
EMA is a sound alternative to informant ratings of functional performance. Though not technically a performance-based assessment and actually akin to ongoing in-person observation, EMA shares several critical features with performance-based assessments. Participants are assessed in real time while performing activities. They are queried as to their current activities and with whom they are in contact. They are occasionally asked to provide rating information regarding their mood, current behavior, and level of autonomy. This strategy involves sampling of behavioral activities in real time, either with diary methods (Stone et al., 2000), paging strategies (Swendson et al., 2000), or with smartphone assessments (Freedman, Lestor, McNamara, Millby, & Schumacher, 2006). These strategies have many advantages in adherent populations, including the ability to use smartphone GPS technology to identify the locations of respondents and their speed and trajectory of motion. As noted later, these technological strategies have the advantage of contemporaneous assessment while not requiring participants to engage in burdensome reporting activities. As noted earlier, measures of functional performance have also been evolving, which attempt to assess an individual’s ability to perform everyday activities.
EMA was initially delivered with paper-and-pencil logs based on timers, pagers, or other notifications (Stone et al., 2000). With the advent of personally available high technology (e.g., PDAs, smartphones), EMA is now much more highly automated. This automated technology allows for several critical pieces of information to be obtained. For example, a momentary assessment allows for assessment of where one is, what he or she is doing, with whom, with what level of satisfaction, and with what level of assistance. Current smartphone technology allows for use of the GPS feature on the phone, which makes it possible to see where a person is and at what rate he or she is moving, if not stationary. There are several benefits of this strategy.
The first benefit is an intrinsic validity assessment. If the participants say that they are on a bus and they are not moving or say that they are at home while moving 65 miles per hour, then critical validity information is collected. If a participant who is impaired is on the bus going to a medical appointment on his or her own, then that would generally be a good outcome unless he or she is going with his or her mother who has to accompany him or her, which would be a less significant functional achievement, unless, of course, that was the intention or intervention goal.
The second benefit is also related to validity, in the domain of response bias. With EMA, a strategy can be developed to avoid bias, in that participants can be sampled for their behavior prior to being assessed with other, reporting-based, methods, which allows for an additional assessment of self-report accuracy and validity. Thus, both recollection accuracy and any response biases can be evaluated through comparison of the data collected before the self-report assessment and the self-reported functioning after the intervention.