Edna: A Mobile Ecological Momentary Assessment Platform for Near Real-Time Dietary Surveillance

This dataset accompanies the Edna Usability Study, an evaluation of a mobile ecological momentary assessment (EMA) app for near real-time dietary surveillance, run under free-living conditions across three iterative development rounds. It contains one row per participant, with app-usability scores, engagement metrics, and demographic, anthropometric, and health characteristics. It is prepared for open reuse under the FAIR principles (Findable, Accessible, Interoperable, Reusable). WHAT IS IN THIS DEPOSIT schembre_edna.csv: the dataset, 146 participants × 29 variables, one row per participant. UTF-8, comma-delimited. edna_data_dictionary.csv: human-readable codebook, every variable with a label, description, data type, units, and allowed values. datapackage.json: machine-readable schema (Frictionless Data "tabular-data-package"), including field types, primary key, and a SHA-256 checksum of the data file. STUDY AT A GLANCE Participants used the Edna smartphone app to record their eating events over roughly two weeks under one of two prompting modes. In Event mode, the participant opened the app and logged eating events themselves. In Interval mode, the app prompted the participant at intervals to report whether they had eaten. The app was refined between rounds based on participant feedback. The study measured how usable participants found the app (System Usability Scale) and how much they engaged with it (how many days they used it, and that as a share of the study window), alongside their demographic and health profile. Participants were included if they used the app on at least three days and returned a valid usability score. Participants: 146 across three rounds (Round 1: 46, Round 2: 45, Round 3: 55), of whom 72 were assigned to Event mode and 74 to Interval mode. Reported sex: 84 female, 61 male, 1 intersex. VARIABLE SUMMARY The 29 variables fall into five groups; see the codebook for the full definition of each. Identifiers and design: subject_id, randomization (Event or Interval), survey (Round 1, 2, or 3). Usability and engagement: sus_score, engagement_pct, app_days_used. Demographics: age, region, sex, race, ethnicity, relationship, children under 18y, employment, studying. Anthropometrics: height_in_inches, weight, bmi. Health and chronotype: eleven self-reported diagnosis fields (none, hypertension, thyroid disease/hypothyroidism, pre-diabetes, type 1 diabetes, type 2 diabetes, high cholesterol, low HDL cholesterol, high triglycerides, obesity) and chronotype. MISSING VALUES Missing values are coded as NA. A small number of implausible self-reported values (one weight, one BMI, one age) were set to missing during cleaning. The codebook notes any variables defined only for a subset of participants. DATA PROCESSING The released file was derived from raw app exports and survey responses with a documented pipeline. Data were restricted to participants who used the app on at least three days and returned a valid System Usability Scale score. App engagement was summarised per participant as days used over the roughly 14-day study window. Demographic, anthropometric, and health variables were drawn from the enrolment survey and joined to each participant's usability and engagement summary. Implausible anthropometric and age values were set to missing before release. PRIVACY AND ETHICS The dataset is de-identified. Participants are represented by pseudonymous study IDs (Mxxx) that cannot be linked to names, contact details, or device identifiers, none of which are included. Direct identifiers collected during screening were never part of this file. Collected under IRB ID: STUDY00007754.