Table 3:

Measurement instruments used

Variables	Measurement instrument	Range of the response scale
Baseline characteristics (demographic data)	Online questions about gender, age, family situation, education level, nature of employment/course, years of work experience, number of working hours per week
Primary outcome
Mindfulness skills	FFMQ-NL total: Dutch version of the Five Facet Mindfulness Questionnaire (Baer et al., 2008; De Bruin et al., 2012) Subscales: Observing Describing Acting awareness Non-judging Non-reactivity	1 (never or almost never) to 5 (very often or always)
Secondary mental health outcomes
Burn-out	UBOS-L Utrechtse Burn-Out Schaal-Leerkrachten (Utrecht Burn-Out Scale—Education) (Maslach and Jackson, 1981; Schaufeli et al., 1996; Schaufeli and Van Dierendonck, 2000) Subscales: Emotional exhaustion Mental distance Personal accomplishment	0 (never) to 6 (always/daily)
Stress	DASS stress: subscale stress of the Depression, Anxiety, Stress Scales (Nieuwenhuijsen et al., 2003)	0 (not at all or never applicable) to 3 (certainly or mostly applicable)
Sleep quality complaints	VBBA subscale (Van Veldhoven et al., 2014)	0 (no) to 1 (yes)
Positive emotions	Job-related Affective Well-being (JAWS) Scale, positive emotions subscale (Van Katwyk et al., 2000; Schaufeli and Van Rhenen, 2006)	1 (never) to 5 (often)
Negative emotions	JAWS Scale, negative emotions subscale (Van Katwyk et al., 2000; Schaufeli and Van Rhenen, 2006)	1 (never) to 5 (often)
Work engagement	UWES Utrecht Work Engagement Scale (Dutch; UBES) (Schaufeli et al., 2002; Schaufeli and Bakker, 2003) Subscales: Vigour Dedication Absorption	0 (never) to 6 (always/daily)
Perceived general health	SF-36v2, perceived general health: Short-Form 36 Health Survey, version 2 (Van der Zee and Sanderman, 2012)	1 (poor) to 5 (excellent)
Organizational commitment	ACS: Affective Commitment Scale, subscale of the Organizational Commitment Questionnaire (OCQ) (Smeenk et al., 2006)	1 (I totally disagree) to 5 (I totally agree)
Work performance
Work performance and work behaviour	IWPQ: Individual Work Performance Questionnaire (Koopmans et al., 2014) Subscales: Task performance Contextual performance Counter-productive work behaviour	0 (rare) to 4 (always)
Personal competencies
Occupational Self-Efficacy	Occupational Self-Efficacy scale (Rigotti et al., 2008)	1 (totally disagree) to 6 (totally agree)
Taking distance	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Work-related perceptions/job demands
Work pace and workload	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Emotional demands	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Negative work–home interaction	Survey Work-home Interaction-NijmeGen (SWING), negative work-home interaction subscale (Geurts et al., 2005)	0 (never/almost never) to 3 (always/almost always)
Negative home–work interaction	SWING, negative home-work interaction subscale (Geurts et al., 2005)	0 (never/almost never) to 3 (always/almost always)
Work-related perceptions/job resources
Autonomy	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Feedback	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Relationship with colleagues	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Relationship with superior	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Relationship with students	VBBA subscale (Van Veldhoven et al., 2014)	0 (never) to 3 (always)
Other
Evaluation of the additional organizational health intervention. Only for IG2.	Four online questions about chosen problem, method of working, joint approach, achieved results	1 (very bad/certainly not) to 5 (very good/certainly)