Background: Non-adherence to prescription medications is exhibited by approximately 50% of patients and is a primary cause of treatment failure, morbidity, and mortality, resulting in an estimated $300 billion in potentially avoidable U.S. health care costs each year (1, 2). Increasing adherence may improve health outcomes and reduce costs, even more so than the advent of new medical treatments (1, 3). Such efforts, however, have been limited by the lack of objective measures of adherence (3). Adherence electronic monitoring devices (AEMDs) are the most objective and preferred measurement strategy for clinical practice and research, but lack indpendently-obtained (versus manufacturer-provided) accuracy and usability data.