Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet

Background and Aims: While there are considerable benefits to Ecological Momentary Assessment (EMA), poor compliance with assessment protocols has been identified as a limitation, particularly in substance users. Our aim was to identify the pooled compliance rate of EMA studies in substance users and examine variables that may influence compliance with EMA protocols, such as the length and frequency of assessments. Design: A meta‐analysis and meta‐regression of all possible studies (randomized controlled trials and longitudinal) which incorporated EMA protocols, examining substance use. Setting: Studies took place from 1998 to 2017, in numerous countries world‐wide. Participants: One hundred and twenty‐six studies were identified, contributing a total of 19 431 participants (52.32% male, mean age = 28.86). Measurements: Compliance data, the proportion of responses to the study protocol, were extracted from each study alongside prompt frequency, total length of assessment period, substance use population and device used to administer EMA prompts. Findings: The pooled compliance rate across all studies was 75.06% [95% confidence interval (CI) = 72.37%, 77.65%]. There was no evidence that compliance rates were significantly associated with prompt frequency [ Q (3) = 7.35, P = 0.061], length of assessment period [ Q (2) = 2.40, P = 0.301], substance type [ Q (3) = 6.30, P = 0.098] or device administration [ Q (4) = 4.28, P = 0.369]. However, dependent samples (69.80%) had lower compliance rates than non‐dependent samples [76.02%; Q (1) = 4.13, P = 0.042]. Conclusions: The pooled compliance rate for Ecological Momentary Assessment studies in substance‐using populations from 1998 to 2017 was lower than the recommended rate of 80%, and was not associated with frequency or duration of assessments.

Objective: Intensive ambulatory assessment, such as ecological momentary assessment (EMA), is increasingly used to capture naturalistic patient-reported outcomes. EMA design features (eg, study duration, prompt frequency) vary widely between studies, but it is not known if such design decisions influence potential subjects’ willingness to participate in a study. We hypothesise that intentions to participate will be higher in studies that are less burdensome and have higher reward (eg, compensation). Design: This experimental study examined if four EMA study design features (study duration, prompt frequency, prompt length, compensation) affected intentions to participate in a hypothetical EMA study and participation appraisals (eg, participation effort). Participants were randomly assigned to conditions (reflecting a fully crossed design of the four features, each with two levels). Each condition presented a vignette describing a study (each a unique combination of design features) and asked them to report on likelihood of participating and study appraisals. Participants: A convenience sample of participants (n=600; 46% female, M age=40.39) were recruited using an online service. Primary and secondary outcome measures: Primary outcomes were willingness to participate (No/Yes) and reported participation likelihood (0–100 scale). Secondary outcomes included appraisals of interest, enjoyment, effort, and if the study makes a valuable contribution to science. Results: We examined main effects, and two-way interactions for participation likelihood, across study design features. Overall, reported willingness to participate and participation likelihood were high (89%, M =83.90, respectively). Shorter study duration, fewer prompts, shorter prompts and higher compensation increased willingness to participate and elicited higher participation likelihood (each associated with ~6%–8% increases). Findings suggested that more intensive studies were judged as somewhat less interesting and enjoyable, and requiring more effort. Conclusion: Hypotheses were generally supported. Design features influence behavioural intentions to participate in, and appraisals of, EMA studies. Implications for participant recruitment and generalisability, and remaining research questions, are discussed.

We examined the acute bidirectional relationships between affective states and moderate-to-vigorous physical activity (MVPA) or sedentary behavior (SB) in children, and whether perceived stress moderates these associations. A total of 180 children (mean age = 9.6 years, 51.7% female, 53.9% Hispanic) completed a 7-day ecological momentary assessment (EMA) study, where they received 3-7 random prompts per day asking about their current affective states. MVPA and SB during this period were measured by waist-worn accelerometers. Children's and mothers' perceived stress were measured by paper questionnaires. Multilevel models tested the within-person (WP) and between-person (BP) associations of (a) MVPA and SB 30 and 60 min before an EMA prompt with subsequent affective states at the prompt, and (b) affective states at the prompt with MVPA and SB in the subsequent 30 and 60 min after the prompt. Interaction terms were used to assess whether children's and mothers' perceived stress moderated these associations. Children reported a higher positive affect after engaging in more MVPA than usual (WP; β = 0.04, SE = 0.02, p < .05) and a lower positive affect after spending more SB than usual (WP; β = -0.02, SE = 0.01, p < .05) in the previous 30 min. Children's affective states were unrelated to time in MVPA and SB within the subsequent 30 min. Parent's perceived stress level attenuated the relationship between children's time spent in MVPA 60 min before a prompt and self-reported positive affect at that prompt (β = -0.01, SE = 0.01, p < .05). MVPA and SB acutely impacted children's psychological well-being, with the benefits of MVPA on positive affect across longer intervals attenuated among children whose mothers had higher perceived stress. (PsycINFO Database Record