What this trial measures

• Area under the receiver operating curve (AUC)Weeks 5 and 6 of data collection

  Performance of the eating disorder behavior prediction models will be evaluated by computing the area under the receiver operating curve (AUC) for each participants' models on two-weeks of held out (test) data (collected during weeks 5 and 6 of the data collection procedure). The AUC can take on values between 0 and 1, with higher values indicating superior model performance.

• Brier ScoreWeeks 5 and 6 of data collection

  Performance of the eating disorder behavior prediction models will be evaluated by computing the Brier score for each participants' models on two-weeks of held out (test) data (collected during weeks 5 and 6 of the data collection procedure). The Brier score can range from 0 to 1 with lower values indicating less model error (i.e., better model performance).

• Binge eatingWeeks 7 through 16 of data collection

  Binge eating occurrence during the data collection protocol will be measured. Binge eating at each ecological momentary assessment survey will be assessed by the question, "Thinking about your most recent eating episode, did you experience loss of control?" (Answer choices = Yes or No).

• Dietary restrictionWeeks 7 through 16 of data collection

  Dietary restriction will be measured during the data collection protocol. Dietary restriction will be assessed at each ecological momentary assessment survey by the questions, "Thinking about your most recent eating episode, did you limit the amount of food you ate to influence your shape?", "Thinking about your most recent eating episode, did you exclude specific foods to influence your shape or weight?", and Since the last survey, have you skipped a meal or snack?" (Answer Choices = Yes or No).

• Compensatory behaviorsWeeks 7 through 16 of data collection

  Dietary restriction will be measured during the data collection protocol. Dietary restriction will be assessed at each ecological momentary assessment survey by the questions, "Since the last survey, have you engaged in any of the following? Self-induced vomiting," "Laxative use (to influence shape or weight)," "Diuretic use (to influence shape or weight)," "Diet pill use (to influence shape or weight)," "Exercise (to influence shape or weight)," and "Other behavior to influence shape or weight" (Answer Choices = Yes or No).

• Feasibility and Acceptability QuestionnaireEnd of study assessment (after week 16 of data collection)

  Acceptability will be evaluated via the Feasibility and Acceptability Questionnaire. These data will be collected after participants have completed the 16 weeks of data collection using the EDDI app. Mean ratings ≥ 5 (on the seven-point Likert rating scales) on acceptability items will be considered to indicate acceptability. The response scale is as follows: 1=Strongly Disagree 2=Disagree 3=Disagree a little 4=Neither agree nor disagree 5=Agree a little 6=Agree 7=Strongly Agree, with higher scores indicating greater acceptability.

• System Usability ScaleEnd of study assessment (after week 16 of data collection)

  Acceptability will be evaluated via the System Usability Scale. These data will be collected after participants have completed the 16 weeks of data collection using the EDDI app. Mean ratings ≥ 4 (on the five-point Likert rating scale) on System Usability Scale items will be considered to indicate acceptability. The response scale runs from 1 = Strongly Disagree (minimum value) to 5 = Strongly Agree (maximum value), with higher ratings indicating greater usability. Items 2, 4, 6, 8, and 10 will be reverse coded to align with higher ratings indicating greater usability.

• Percentage of Eligible Participants EnrolledThrough study completion, an average of 4 months

  Feasibility of the EDDI app will be evaluated by computing the percentage of eligible participants enrolled. This will be computed by dividing the number of enrolled participants by the total number of eligible participants and multiplying by 100. At least 85% of eligible participants enrolled will be considered to demonstrate feasibility.

• Attrition RateThrough study completion, an average of 4 months

  Feasibility of the EDDI app will be evaluated by computing the attrition (drop out) rate. This will be computed by dividing the number of participants who discontinue the study prior to the end of study assessment by the total number of enrolled participants and multiplying by 100. An attrition rate of less than 15% will be considered to demonstrate feasibility.

• Percentage of JITAIs Producing Skill UseThrough study completion, an average of 4 months

  Feasibility of the EDDI app will be evaluated by computing the percentage of JITAIs that produce participant-reported skill use. This will be computed by dividing the instances of reported skills used by the total number of delivered JITAIs and multiplying by 100. JITAIs producing skill use at least 80% of the time will be considered to demonstrate feasibility.