Value Set Hub: Software for developing and curating high-quality value sets.

Terminology value sets are central to research studies using real-world patient data. We describe the considerable challenges that arise when researchers develop value sets for their studies or reuse those made by others. We present Value Set Hub (VS-Hub), software to overcome these challenges, describing its design, implementation, features, use in the field, lessons learned, and future directions. Over a five-month period, VS-Hub has been used by over 200 users and has been used in the development and curation of 95 recommended value sets for commonly studied conditions, treatments, and lab tests. Particular innovations include the presentation of multiple value sets on the same screen for easy comparison, the display of compared value sets in the context of vocabulary hierarchies, the integration of these analytic features and value set authoring, and value set browsing features that encourage users to review existing value sets that may be relevant to their needs.