Human Functioning as the Third Health Indicator: Epidemiology, Classification, and Measurement

Human functioning is increasingly recognized as the third indicator of health, complementing mortality and morbidity. While these indicators describe survival and disease, they do not fully capture how people live, interact with their environments, and participate in society. Advances in epidemiology, classification systems, and measurement science now make it possible to conceptualize and quantify functioning with greater precision. Epidemiological approaches can identify patterns and determinants of functioning across populations, classification frameworks provide a common language for describing functioning domains, and innovations in measurement tools enable reliable and comparable data collection. Together, these developments position functioning as a third pillar in health reporting and support more informed clinical practice, rehabilitation planning, and public health decision-making.In parallel, there is a growing need to move beyond evaluations of single, isolated interventions towards research that examines clinical pathways and complex interventions in health and rehabilitation. Many contemporary interventions are multi-component, context-dependent, and unfold over time through interactions between individuals, services, and systems. In this context, functioning provides a unifying outcome and analytical lens to capture change across domains and stages of care, supporting a more nuanced understanding of how complex interventions work, for whom, and under which circumstances—consistent with current frameworks for Complex Interventions in Health.The goal of this Research Topic is to bring together high-quality contributions that demonstrate how human functioning can be understood, measured, classified, and applied through epidemiology, standardized classification frameworks, and robust measurement approaches. We welcome submissions ranging from methodological innovations in measurement and classification to epidemiological analyses and pathway-based studies of complex interventions that use functioning data to inform clinical decisions, service planning, rehabilitation strategies, and policy evaluation. Accepted manuscript types include original research, methods papers, and reviews. Submissions should clearly show how functioning can strengthen health assessment and support evidence-based decision-making at individual, clinical, and population levels. Topic editors: Adrian Martinez-De La Torre, Thomas Maribo Source: https://www.frontiersin.org/research-topics/76201/human-functioning-as-the-third-health-indicator-epidemiology-classification-and-measurement