A subcohort of adult participants filled in the Volunteer Functions Inventory in the context of an additional questionnaire, QACT.

The Volunteer Functions Inventory (VFI) is a measurement instrument aimed at assessing the motives to volunteer¹⁾.
The VFI is the most widely used instrument for assessing volunteer motivations because of its theoretically sound basis as well as its good psychometric properties²⁾.

Six motivational functions are proposed:

1. Values: The opportunities that volunteerism provides for individuals to express values that are important to the self, related to altruistic and humanitarian concerns for others;
2. Understanding: The opportunity for volunteers to gain and sustain knowledge, skills and abilities;
3. Social: Volunteering offers opportunities to improve social relationships, it helps individuals to fit in and get along with social groups that are important for them;
4. Career: Participation in voluntary work may increase future job opportunities;
5. Protective: Participation in voluntary work can protect oneself from negative feelings about oneself, it can help the individual to eliminate negative aspects surrounding the ego;
6. Enhancement: By participation in voluntary work the individual can enhance his/her self-esteem, it centers on ego growth and development.

An overview of validation studies of the VFI can be found in . Several VFI items have been translated into Dutch [18]. However, the total VFI has not been translated, nor validated in the Dutch language yet. The current study, therefore, aims to translate the VFI to the Dutch language and to evaluate the psychometric Int. J. Environ. Res. Public Health 2019, 16, 3106 3 of 14 properties of the Dutch-translated VFI within a sample of current volunteers aged 60 to 80 years in order to assess its cross-cultural validity.

Participants were given a list of statements reflecting reasons for doing volunteer work. They were instructed to indicate on a 7-point Likert scale how well each statement applied to them. In addition, they were asked in how far the given reason would be a reason to start doing volunteer work.