Procedure
To obtain a representative volunteer sample, we recruited from 10 nongovernmental
organisations operating in the social domain (61.3% of
respondents) and in the educational domain (38.7% of respondents). The
questionnaires were distributed at the end of regular meetings in the respective
organisations where volunteers are briefed about new and ongoing volunteering
projects. This was accompanied by a short verbal clarification of
the study, where special emphasis was put on confidentiality, anonymity of
responses, and voluntary participation. Our procedure resulted in a response
rate close to 100 per cent (a small number of questionnaires could not be used
due to incompleteness).