In the search for data more powerful, resources are often created by combining data from different sources, e.g. administrative and survey data. Such merged data sets could only serve the scientific community, if they are high quality. Thereby data documentation is of vital importance, and no easy task. Data that accrued out of two different sources needs an adjusted, standardized and easy to understand documentation. The DDI standard can fulfill these needs.

The Institute for Employment Research (IAB) and the German Institute for Economic Research (DIW Berlin) are two major data providers in Germany, the IAB for administrative data and the DIW Berlin for survey data (German Socio Economic Panel, SOEP).

Within this presentation the authors will show the challenges in implementing a standardized metadata documentation, the importance of a well-suited documentation for data quality and the advantages of an agreed data documentation for comparison and combination of datasets. The focus will lie on the Data Documentation Initiative (DDI), a metadata standard for research data.