Respondent driven sampling as a new method for recruiting vulnerable population groups


Persons with a migration background are often underrepresented in health studies using standard recruitment methods. Such a selective sample composition may seriously distort investigations on the influence of a migration background. The Respondent Driven Sampling (RDS) represents an alternative to conventional register-based samples. The RDS recruitment follows the principle of snowball sampling: specifically selected initial study subjects (seeds) are interviewed or examined, and receive a limited number of coupons. These function as financial incentives to encourage the seeds to recruit new participants. The new participants in turn receive coupons to motivate them to recruit further participants, and so forth. The relationship between the persons recruiting and those to be recruited is documented via serial numbers on the coupons. Compared to other snowball sampling methods, the evaluation method of the RDS-procedure provides the potential to generate an unbiased estimate by means of special weighting procedures and adjustments of the design effect.

The purpose of this study is to examine the practicability, costs and success of the RDS in reaching vulnerable population groups by means of a systematic comparison with standard recruitment methods (registration office sample). To this end, a sample will be recruited via RDS in two districts in Bremen that are very diverse in terms of the socioeconomic and cultural composition of the resi-dents. Parallel to this, a comparison group will be formed in the same districts via standard recruit-ment methods that are applied as part of the UPWEB-project currently in progress.

Funding period

Begin:   January 2017
End:   November 2017


  • BIPS funding (Institute's intramural fund)


Dr. phil. Tilman Brand