Evaluating an Alternative Frame for Address-Based Sampling in Germany: The Address Database of the Deutsche Post Direkt

In Germany, the population register with individual addresses can be utilized for address-based sampling. However, unlike in countries with a centralized register, local authorities in Germany administer their own registers. This not only makes sampling for a nation-wide survey more costly and cumbersome but may also result in gaps in the gross sample, as selected municipalities can refuse the use of their register for sampling purposes. If alternative municipalities to substitute refusals are not available, different sampling methods are required. With the present study, we aimed at testing the usability of the Address Database of the Deutsche Post Direkt (ADB-DPD) as an alternative frame for address-based sampling in Germany. We simultaneously carried out two surveys in the German city of Mannheim with gross samples of 3,000 each; one drawn from the city’s population register and the other from the ADB-DPD. Our findings suggest that the ADB-DPD performs well, both in terms of survey response and up-to-dateness. Due to relatively low costs and the fast provision of addresses, the ADB-DPD can be particularly attractive for survey projects with limited budgets and tight schedules. However, these benefits come at considerable cost. First, the usage of the ADB-DPD is limited to self-administered surveys. More importantly, in the net sample of the DPD survey, women and young persons were considerably under-represented. This indicates coverage issues for which DPD provided no further information. Based on our analysis, we provide practical remarks on the usability of the ADB-DPD and suggest avenues for future research.