Enhancing Survey Participation within Diverse Respondent Groups

PIs: Dr. Jannes Jacobsen (DeZIM), Dr. Michael Weinhardt (DZA), Dr. Mareike Bünning (DZA)

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The project examines how participation of migrants—particularly Turkish nationals—in large-scale surveys and panel studies can be improved. Stronger inclusion of these groups is essential for adequately capturing their living conditions and integration trajectories and for avoiding biases in population data. As people with a migration background make up around 30 percent of Germany’s population, their inclusion is crucial for realistically reflecting societal developments.

In cooperation with the German Centre of Gerontology (DZA) and the Research Centre of the Federal Office for Migration and Refugees (BAMF-FZ), adaptive survey designs are developed and tested to build trust, reduce access barriers, and foster long-term participation.

In collaboration with representatives of the Turkish community, culturally sensitive recruitment strategies and adapted field materials have been developed. The DZA conducted qualitative preliminary studies in the form of expert interviews and focus groups to identify key experiences, barriers, and entry points for effective outreach. The developed strategies and materials are then tested under real field conditions across multiple survey phases—from the initial invitation to follow-up waves. The results feed into existing studies such as the German Ageing Survey (DEAS) and form the basis for evidence-based recommendations to improve data collection. In this way, the project contributes to more inclusive, representative, and forward-looking social research.

• Despite various efforts in survey research, migrants and their descendants remain underrepresented in large population studies. Their lower participation rates lead to biases and hinder reliable analyses. While it is known that factors such as age, education, or trust in institutions influence participation, there is still a lack of systematic empirical evidence on how migration-specific barriers—such as linguistic, cultural, or experiential differences—can be reduced through targeted survey designs.
• The project addresses this gap by experimentally examining which forms of outreach, survey design, and recruitment effectively increase migrant participation, thereby providing an empirical basis for more inclusive and methodologically robust social research.

The project aims to increase the participation of migrants—particularly Turkish nationals—in large-scale surveys and panel studies. This will improve the measurement of their living conditions and integration trajectories and reduce biases in population data.

At its core is the development and experimental testing of adaptive survey designs that build trust, reduce access barriers, and promote long-term participation in scientific studies. Target group–specific recruitment strategies, adapted questionnaire content, and different survey modes are systematically tested and compared with standard procedures. The findings will be integrated into existing studies such as the German Ageing Survey (DEAS) and will serve as the basis for evidence-based best-practice guidelines to make social research in Germany more inclusive and methodologically sound.

In cooperation with the Federal Office for Migration and Refugees (BAMF), a sample of Turkish nationals is drawn from the Central Register of Foreigners (AZR). In the first wave, around 10,000 individuals are contacted and randomly assigned to different survey modes (face-to-face, postal, online).

Invitation letters, questionnaire content, and the panel consent question are systematically varied to assess their effects on participation and retention. Fieldwork for the first wave is conducted by the SOKO Institute, while the second wave is carried out at DeZIM. This experimental approach makes it possible to identify strategies that sustainably increase participation and strengthen trust in social science surveys.

The qualitative phase of the project shows that lack of trust, social exclusion, and a limited sense of belonging are key reasons for the low participation of Turkish migrants in surveys. Language barriers also play a role, but primarily in a symbolic sense—as an indication of a lack of recognition and respect from researchers.

Successful recruitment therefore requires not only linguistic adaptation but, above all, relevance, recognition, and the building of long-term trust relationships.

Expert interviews further highlight that insider interviewers—individuals with a similar cultural background—can facilitate access to respondents and strengthen trust. Addressing participants in Turkish often acts as a door opener. Overall, the findings underline that successful recruitment depends less on language alone and more on relevance, recognition, and sustained trust-building.