The Registering Researchers in Authority Files Task Group has examined a range of researcher registration and profiling services. A number of approaches to providing authoritative researcher IDs have emerged, but they tend to be limited by discipline, affiliation, or publisher. The Task Group developed use cases and functional requirements for researcher ID management systems and then compared the functional requirements against a sample of currently available systems to identify gaps, challenges and opportunities. A key objective of this work was to understand how the various types of researcher ID schemes can be leveraged to support improved discoverability of research output for individual authors and institutions.