Table 1.

Overview of engagement strategy codes.

Strategies and attributes			Definition
Program design strategies
	Consultation	Processes or activities that seek to obtain verbal or conceptual input about the design or delivery of an intervention
	End user consultation a	Consultation with users of the program, defined as parents or caregiver program participants
	Stakeholder consultation	Consultation with stakeholders associated with the program, defined as service or program providers or clinicians
	Academic expert consultation	Consultation with academics with expertise in the program’s content
	Testing	Processes or activities which allow users to engage with a prototype, and provide input about the experience of using the intervention
	End user testing	Testing with users of the program, defined as parents or caregiver program participants
	Stakeholder testing	Testing with stakeholders associated with the program, defined as service or program providers or clinicians
	Academic expert testing	Testing with academics with expertise in the program’s content
Enrollment strategies
	Targeted recruitment strategy	Efforts to increase the likelihood that the intended population or sample will be recruitedb
	Partnerships	Efforts to collaborate with and involve relevant communities or services in the recruitment of intervention usersb
	Practical support	Provision of services or materials that facilitate users to use and engage with the program (eg, loaning of technological equipment, technical assistance, provision of childcare).
Program-specific strategies
	Content- behavior change techniques	Tools, features, or strategies used in the intervention to promote behavior change
	Goal-setting	Encourages the user to list and set goals relevant to the intervention’s contentb
	Action plans	Supports the user to list specific behaviors or actionable strategies that they intend to completeb
	Feedback	Allows the user to receive feedback (may be automated or via an interventionist)b
	Self-monitoring tools	Tracks a user’s performance or status to support achieving goalsb
	Content: rewards	Features that offer reward upon user’s performance of a target behavior
	Praise	Offers praise to the end user on any occasionb
	Content: summaries	Features which provide the user with a summary of intervention content or activityb
	Content: social support features	Features that facilitate the receipt of social support
	Web-based discussion forums	Provides the opportunity for users to see other users use the intervention or performing the target behaviorb
	Content: supplementary resources	Features which centralize a range of resources relevant to the user or interventionb
	Content: reminders	Features that serve to remind users about using the intervention or performing target behaviors
	Delivery: mode	Intentional use of a given technology mode, thought to enhance engagement, to deliver intervention contentb
	Delivery professional support features	Features that enable remote contact with a professional
	Clinical support	Provides clinical, coaching, or therapeutic support to facilitate behavioral changeb
	Nonclinical support	Provides nonclinical support to facilitate use, eg, technical, encouragement, progress monitoringb
	Delivery: control features	Features that make users feel in control of and free to make choices about how to interact and use the intervention
	All-at-once	Users receive the whole intervention at once and are not required to complete predetermined steps to progress through the intervention
	Reviewability	Users have the ability to review old contentb
	Delivery: tunneling	Features that lead users through predetermined steps to progress through intervention
	Delivery: novelty	Features that provide the user with regular content updates
	Delivery: ease of use	Features that support the use of the intervention to feel natural
	Delivery: personalization	Features that deliver content in a way that is adapted to the user on an individual level
	Delivery tailoring	Features that deliver content in a way that is adapted to factors relevant to the user’s potential needs, interest, use context or other factors relevant to the user’s social group
	Delivery: message tone	The terminology and wording used to communicate the content’s message
	Credibility features	Features whose presence is designed to inculcate a feeling of trust or familiarity within the user
	Narrative	The presence of a storyline to deliver intervention content or concepts
	Delivery: esthetics and design	Visual features that are designed to be attractive to users
	Delivery: guidance	Features that provide the user with tutorials or how-to-use guides to inculcate feelings of comfort and ease of use
	Delivery: interactivity	Features that promote a two-way flow of information between the intervention and its user
	Rehearsal	Features that invite the user to rehearse a behavior or content of the intervention
	Challenge	Features that invite the user to test or apply their knowledge of program conceptsb
	Gamification	Features that stimulate users to compete with themselves or the program in achieving a target behavior
	Reflection	Features that invite the user to reflect on the program content or their behaviorb
Research involvement strategies
	Reminders	Features that serve to remind users about using or completing the program’s research component (eg, questionnaires, or measures)
	Rewards and incentives	Features that offer reward upon user’s use or completion of the program’s research component (eg, questionnaires, or measures)

^aStrategy subtypes are italicized.

^bDefined by authors.