Data for the German Survey on Volunteering (FWS) has been collected five times so far. The data collections of the years 1999, 2004 and 2009 were carried out by TNS Infratest. Since the end of 2011, the German Centre of Gerontology (DZA) has been responsible for the scientific direction of the Survey on Volunteering. The interviews for the fourth (FWS 2014) and fifth wave (FWS 2019) were conducted by infas Institute for Applied Social Science.
The German Survey on Volunteering was conducted in all waves as a standardized telephone interview (CATI; Computer Assisted Telephone Interview). The population is the resident population of Germany in private households aged 14 and above.
Since 2014, a 'dual frame approach' has been used to conduct interviews also via mobile phones, in particular to reach people who do not have a fixed line connection (so-called 'mobile-onlys'). To improve the inclusion of people with a migration background, interviews have been conducted not only in German but also in five other languages (English, Arabic, Russian, Turkish and Polish) since 2014.
The sample consists of a basic sample stratified by federal states and a supplementary sample, which enables detailed analyses for federal states with smaller population.
At the beginning of the interview general questions are directed to all participants. Then, questions are asked in order to identify whether a person is engaged in voluntary work or not. Persons who volunteer, will be asked questions about their voluntary work. Persons who don‘t volunteer will be asked questions e.g. about previous voluntary activities and potential volunteering in the future. At the end of the survey, further questions are again directed to all participants.
The survey instrument has been continuously modified and complemented over the years. At the same time, the continuity in the central survey contents has been maintained in order to ensure comparability over time.
Two different weighting factors can be used to evaluate the data: One weighting factor including information on gender, age, community size classes (BIK) and federal state and one weighting factor including the above-mentioned characteristics as well as school education.
The number of respondents has increased significantly since the first survey:
- FWS 1999: 14,922
- FWS 2014: 15,000
- FWS 2009: 20,005
- FWS 2014: 28,690
- FWS 2019: 27,762