Table 3.

Reliability of questionnaires (Cronbach’s alpha at baseline and ICC)

Scale	All participants, baseline			Validation school only, one-month test–retest (N = 169)
	Cronbach's alpha			Intraclass correlation coefficient	95% CI (lower)	95% CI (upper)	p
	All	Peer learners	Peer educators
General help seeking	0.84	0.85	0.80	0.69	0.69	0.82	< 0.001
Self-help confidence statements	0.78	0.80	0.72	0.67	0.66	0.80	< 0.001
Mental health knowledge	0.59	0.55	0.65	0.50	0.47	0.68	< 0.001
Mental health knowledgea	0.60	0.54	0.68
Sense of belonging: peer relationships	0.80	0.78	0.80	0.79	0.76	0.86	< 0.001
SWEMWBS	0.85	0.84	0.84	0.73	0.69	0.82	< 0.001

^a10 items removing two with low correlations; SWEMWBS Short Warwick-Edinburgh Mental Wellbeing Scale