Low patient medication adherence is one of the 2 largest unsolved gaps in health care, with the other being suboptimal therapy prescription. For example, oral anticoagulation (OAC) is firmly recommended in patients with atrial fibrillation at high risk for stroke, but typically about half of the eligible patients do not receive OAC.1 Of those patients who receive OAC, approximately half will not begin therapy or will stop therapy within a year,2 and of those patients persisting with an OAC regimen, only half take their pills consistently as prescribed.3 As a consequence, most patients will not reap the full health benefits from proven therapies such as OAC. There is rising interest in medication adherence research,4 but these well-meaning efforts have not yet led to substantial and reliable adherence improvements when looking at the entire adherence research field. Are we perhaps missing the signal of specific interventions?