Table 1.

Study parameters and measurement instruments

Outcome measure	Instrument
Primary outcome measure
Emotional, social and psychological well-being	Mental Health Continuum – Short Form (MHC-SF)
Secondary outcome measures
Loneliness	Loneliness Scale
Depression	Center for Epidemiologic Studies Depression Scale (CES-D)
Consumption of care	Items from the Trimbos/iMTA questionnaire for Costs associated with Psychiatric Illness (TIC-P) and use of psychotropic drugs
Purpose in Life	Purpose in Life Scale
Resilience	Brief Resilience Scale
Social participation	Items from different validated survey studies, such as CBS-POLS and LISS
Health-related quality of life	Dutch version of the EuroQol (EQ-5D)
Moderating measures
Demographics of participants	Gender, age, education, marital status, number of children, cultural background, income, employment status
Demographics of counselors	Gender, age, occupational level, financial situation, cultural background
Work characteristics of counselors	Work experience, work conditions
Work engagement	Utrechtse Bevlogenheid Schaal (UBES)
Work satisfaction	Vragenlijst Beleving en Beoordeling van de Arbeid (VBBA), General Work Satisfaction
Adherence of counselors	Online logs