eHealth Initiative’s Electronic Medication Adherence Collaborative (eMAC) continues to convene multiple stakeholders to identify effective innovation and best practices that improve patient outcomes and save money, through medication adherence. During and in-person meeting on December 12, 2017, eMAC focused on the potential to create an adherence “vital sign,” which providers might use to track patient compliance with treatment plans. This summary contains metrics providers and researchers are currently using to assess patient adherence and other highlights from the meeting. All presentations are located online in the eHealth Resource Center.