I read with great interest Cheng's guest editorial “Defining successful aging: the need to distinguish pathways from outcomes.” The landscape of successful aging literature is littered with pathway – and outcome-oriented conceptualizations, making this differentiation an important issue to address. Further to the notion highlighted by Cheng is the usage (and confounding) of items surrounding successful aging. A recent review of the operational definitions of successful aging highlights the continued heterogeneity of successful aging operationalizations, identifying over 100 unique definitions of successful aging (Cosco et al., Reference Cosco, Prina, Perales, Stephan and Brayne2014). Perhaps as a by-product of this pervasive definitional heterogeneity, there is an equally pervasive conceptual overlap of the constituent components of successful aging. Depending on the definition of successful aging used (and possibly the availability of variables in a dataset and theoretical background of the researcher), the same item may be used as a predictor, component, or outcome of successful aging. While Cheng (rightfully) advocates for the inclusion of psychosocial components into definitions of successful aging, these items are particularly prone to this conceptual confusion. Take, for example, an item specifically identified by Cheng: life satisfaction. Successful aging was originally posited as inextricably linked to life satisfaction; however, subsequently, life satisfaction has been identified as a predictor (Roos and Havens, Reference Roos and Havens1991), indicator (Leonard, Reference Leonard1981), and component (Pruchno et al., Reference Pruchno, Wilson-Genderson and Cartwright2010) of successful aging. Further, several qualitative studies have been conducted with laypersons specifically differentiating between successful aging and life satisfaction, e.g. Fisher (Reference Fisher1995). As Cheng illuminates and these examples highlight, the language of successful aging is rife with conceptual confusion – an inhibitive force in the advancement of the field – that must be addressed.

While it may be unrealistic to expect the development of a single, universally accepted operationalization of successful ageing, it is important to acknowledge the diversity of successful aging conceptualizations, e.g. from culturally and geographically diverse sources, and to look toward the practical utility of successful aging models. In order for models of successful aging to demonstrate real world applicability, it is imperative that these theoretical constructs are investigated in practical settings, e.g. longitudinal population-based cohort studies, and their associations with public health outcomes, e.g. health service utilization, are examined. The successful aging paradigm will be greatly strengthened through the application of well-informed conceptualizations of successful aging that have been validated in real-world contexts.