Table 1.

Overview of the instruments used to evaluate the efficacy of the SoMe intervention.

Outcome Measures		Construct	Cronbach Alpha
Primary outcome variables	12-item Weight and Shape Concern subscales of the Eating Disorder Examination Questionnaire (EDE-Q) [61] e.g., “Have you had a strong desire to lose weight?”	Body dissatisfaction	0.96
	Three 100-point visual analogue scales (VAS) [62] e.g., “I feel satisfied with my body shape”	State body dissatisfaction	-
	10-item Restraint subscale from the Dutch Eating Behaviour Questionnaire (DEBQ) [63] e.g., “Do you deliberately eat foods that are slimming?”	Dietary restraint	0.94
	5-item Strategies to Increase Muscle Size subscale from the Body Change Inventory (BCI) [64] e.g., “How often do you think about changing your level of exercise to increase the size of your muscles?”	Strategies to increase muscles	0.92
Secondary outcome variables	9-items from the Centre for Epidemiological Studies Depression Scale Revised (CESDR-10) [65] e.g., “I had trouble keeping my mind on what I was doing”	Depressive symptoms	0.90
	Single-item Self-Esteem Scale [66] 3-items from the Rosenberg Self-Esteem Scale [67] e.g., “I feel I have a number of good qualities”	Self-esteem	0.71
Exploratory outcome variables	5-items (adapted) from The Sociocultural Attitudes Towards Appearance Scale-3 (SATAQ-3) [68] e.g., “I would like my body to look like people on social media”	Internalization of social media appearance ideals	0.81
	5-item Internalization-Muscular/Athletic Subscale of the Sociocultural Attitudes Towards Appearance Scale-4 (SATAQ-4) [69] e.g., “It is important for me to look athletic”	Internalization of muscular/athletic ideals	0.93
	5-items from the Upward Physical Appearance Comparison Scale (UPACS) [70] e.g., “I tend to compare myself to people I think look better than me”	Upward appearance comparison	0.97

Internal reliability of scale scores is represented by baseline measurement.