Current and emerging measures and methods for evaluating medication adherence behaviors

INTRODUCTION: Medication adherence is a key determinant of treatment effectiveness and health outcomes, yet it remains a major challenge in clinical practice and research. As dynamic and multidimensional behavior influenced by cognitive, emotional, and contextual factors, adherence cannot be fully captured by a single measure. This complexity is further amplified in real-world settings characterized by multimorbidity and polypharmacy. AREAS COVERED: This review examines current and emerging methods for measuring medication adherence. It considers the data sources and computation procedures required. These methods were classified into self-report instruments, electronic monitoring systems, administrative pharmacy claims, and group-based trajectory modeling. It discusses their conceptual basis, strengths, and limitations, highlighting how different methods capture distinct dimensions of adherence behavior. EXPERT OPINION: No single method represents a universal gold standard, and adherence measures are not interchangeable. Selection should be guided by the research objective, whether focused on exposure, determinants, or outcomes. Future advances will depend on integrating complementary methods and adopting longitudinal approaches to better reflect the dynamic nature of adherence and support more effective interventions.