Table 2.

Reliability and sources of independent variables (Cronbach alpha values higher than .70 are considered sufficient).

Category		Content	Cronbach alpha presurvey	Cronbach alpha postsurvey	Source
Button data
	Eating rhythm	Interval between eating occasions per day	—a	—	Button app
		Eating occasions per day	—	—	Button app
	Adherence to use the app	App openings per day to observe visual summaries about eating rhythm	—	—	Button app
Survey data
	Eating rhythm	Daily consumed meals	—	—	List of meals types
	Eating behavior tendencies	Three-factor eating questionnaire (R-15) (scale 0-100)	uncontrolled eating: .77; cognitive restraint: .76; emotional eating: .77	uncontrolled eating: .81; cognitive restraint: .71; emotional eating: .89	[27,28]
	Discontent with eating	Discontent with eating in different meal times (scale 1=never, 5=very often)	—	—	modified from [28]
	Attitudes	General health interest (scale: 1=completely disagree, 7=completely agree)	.81	.80	[30]
	Food-related motives	Food choice motives regarding health, mood, weight control (subscales of food choice questionnaire (scale: 1=not important at all, 4=very important)	health: .75; mood: .80; weight control: .76	health: .74; mood: .88; weight control: .79	[31]

^aNot applicable.