Over the years, the social sciences have become increasingly data intensive. Hence, data repositories must facilitate the identification and location of data. Persistent identification is essential for sustainable and reliable resource discovery and reuse. The use of a persistent identifier (PID) supports data access, referencing data and data citation. However using PIDs pose complex technical and organizational challenges to data providers. This presentation discusses our paper on the use of PIDs within CESSDA ERIC (Consortium of European Social Science Data Archives European Infrastructure Research Consortium). CESSDA ERIC provides its communities with well documented, verifiable and understandable research data. This can be majorly supported by the assignment of PIDs, that are unique on a global scale. In order to find a common approach to the use of PIDs among CESSDA members, CESSDA started the PID project in 2015. For this project, GESIS conducted quantitative and qualitative surveys among CESSDA members, to assess their current status and their needs concerning PID usage. The results of these surveys lay the groundwork for the CESSDA ERIC Persistent Identifier Policy. Those surveys, their results as well as the resulting PID Policy shall be presented here.