This planning project examines the potential for systematic research on data sharing. The planning activities include conferences on normative and empirical issues in data sharing in the social sciences. In the first conference a small interdisciplinary group will identify and clarify these issues and the kinds of empirical inquiries that could provide useful information to assess and resolve them. One or more publications discussing the main normative issues and needed empirical research will result from this conference. The second conference will include members of the first group and some additional participants. It will focus on transforming one high priority empirical question into a viable research project, and proposal on this topic will be submitted to NSF. Issues of data sharing are both central and complex questions for science to address. Little systematic work has been done on them. The project director and potential conference participants are very well qualified to begin these efforts. This project should provide useful results by itself and stimulate future efforts in this field. For these reasons, support in the amount of $15,000 is recommended.