Table 1.

Checklist.

Issues	Considerations
Choice of distal and proximal outcome measure	What distal health outcome is being targeted? What is a suitable proximal outcome and how does it relate to the distal outcome? Is the proximal outcome measurable? Is the proximal outcome likely to change in response to the intervention used? What time duration should we use to derive the proximal outcome? Are sufficient engagement strategies in place to obtain reliable and valid proximal outcome measures?
Intervention options	Which intervention options might be actionable if delivered via mobile device in everyday life? Is the timeliness of content of the intervention option critical? How should the intervention options be delivered? By which mediating variables do you think the intervention option will impact the long-term health outcome? How should this intervention option impact the mediating variables in the near-term? Can you observe/record the near-term impact of this intervention option? How might temporal characteristics of an individual’s psychosocial, behavioural, psychological, or symptomatology factors influence the relative effect of the intervention option? Over what time interval do you think the intervention option will have the largest effect?
Choosing intervention delivery decision points	When is the user at increased risk? When is the user likely to be most receptive/responsive? Are there set times at which the user is most likely receptive/responsive or most likely not receptive/responsive? What means are there to detect in-the-moment receptivity? Can these detections be done in real time? Are there any fixed times at which the user might not be available? Can you detect in-the-moment unavailability? Are data collection and monitoring strategies reliable enough to detect decision points?
Randomising when and what	Determine how much burden a user can tolerate. Decrease probability of randomisation with increased burden and less tailoring
Ethical considerations	Give users control to decide when they do not want to receive interventions In some populations, there should be expert clinically determined cut off points regarding symptom severity that will trigger direct clinical contact. Consider domain science, ethical and self-determination rationales in designing intervention options Do you have m-Health & biostatistics skillsets? Do you have someone in the team who can guide the app developer to gather useful data for analysis? Are you recording what data is missing, when and why?