There are a growing number of institutional services aimed at collecting research data sets that fall outside the scope of large discipline-specific, or government data repositories. Such data sets represent a diversity of formats, may have documentation and curation weaknesses, and are often not easily found. In addition, there are significant variations in approaches in collecting and managing those data. A 2011 survey by Science found that, "even within a single institution there are no standards for storing data, so each lab, or often each fellow, uses ad hoc approaches." The European Commission says, "Different institutions archive their research data in different ways – making access difficult from outside the institution." This paper will present the results of an international survey of research data repositories that collect and manage heterogeneous data sets. The survey will be conducted in January/February 2013 under the auspices of the RDA Long Tail of Research Data Interest Group. The results will provide the broader community with a deeper understanding of the metadata and vocabularies that are currently in use within these contexts, with the aim of developing community-based recommendations to ensure lightweight interoperability and visibility of this type of research data across the globe.