VSAC Category Development Implementation Who Uses Tool CDS Developer Health IT Developer/Vendor Implementers Measure Developer/Measure Steward Payer Eligible Hospital and Critical Access Hospital Eligible Professional and Eligible Clinician The Value Set Authority Center (VSAC) is a central repository for the official versions of value sets that support the electronic clinical quality measures. The National Library of Medicine maintains the VSAC and provides downloadable access to the value sets and the Binding Parameter Specification. The VSAC provides measure developers with tools to search existing value sets, create new value sets, and maintain value set content consistent with current versions of the terminologies they use.