In the mid 1970s, David Sackett and colleagues1 partnered with a group of 250 hypertensive factory workers and their physicians to conduct groundbreaking research on what was then referred to as medication compliance. Using pill counts, the investigators discovered that about half of the workers were taking less than 80% of their blood pressure pills and that the nonadherent workers were less likely to have controlled blood pressure. In the subsequent 40 years, the amount of research dedicated to medication nonadherence increased exponentially (Figure). Health economists have identified medication adherence interventions as opportunities for improving health outcomes while reducing health care costs. Stakeholders ranging from the Agency for Healthcare Research and Quality to the World Health Organization issued calls to action for the implementation of strategies to improve medication adherence. Despite this increased attention, the prevalence of medication nonadherence is as high as ever, and up to 50% of patients remain nonadherent to treatments prescribed for chronic health conditions.2