Table 1.

Specifications Tested in the Irish, American, and British Data Sets

Decision	Hypothesis-generating studies		Hypothesis-testing study
	Ireland	United States	United Kingdom
Operationalizing adolescent well-being	Strengths and Difficulties Questionnaire; well-being: Child Depression Inventory	Well-being: Short Moods and Feelings Questionnaire; Rosenberg Self-Esteem Scale	Strengths and Difficulties Questionnaire; well-being: Short Moods and Feelings Questionnaire; Rosenberg Self-Esteem Scale
Operationalizing digital engagement	Retrospective self-report measure; time-use-diary measures (weekday and weekend separately): (a) participation, (b) time spent, (c) < 2 hr before bedtime, (d) < 1 hr before bedtime, and (e) < 30 min before bedtime	Retrospective self-report measure; time-use-diary measures (weekday and weekend separately): (a) participation, (b) time spent, (c) < 2 hr before bedtime, (d) < 1 hr before bedtime, and (e) < 30 min before bedtime	Retrospective self-report measure; time-use-diary measures (weekday and weekend separately): (a) participation, (b) time spent, (c) < 2 hr before bedtime, (d) < 1 hr before bedtime, and (e) < 30 min before bedtime
Inclusion of control variables	No controls; all controls	No controls; all controls	No controls; all controls