Constructs and indicators are central to the efforts of many researchers who seek to build and test theories and articulate rich narratives about real-world phenomena. For this reason, an extensive discourse exists about their nature. Increasingly, this discourse has become fraught with controversy. Using Bunge’s (1977, 1979) ontology, I examine the nature of constructs and indicators as they are discussed in the extant literature. I define these concepts precisely, disentangle conceptual from measurement issues, and point to ways that discourse about them could better proceed. I show that unidimensional constructs, multidimensional constructs, dimensions, and indicators are all properties in general of a class of things. I also show that only three types of indicators exist—synonyms of the focal construct and succeeding or preceding properties in a pre-order of properties that includes the focal construct. I examine ontologically the notions of content validity, convergent validity, discriminant validity, and internal-consistency reliability and show their problematic nature. I introduce two new concepts, scope validity and the level of concomitance of indicators, that have rigorous ontological foundations. Together, they provide an improved foundation for assessing the construct validity of a set of indicators.
12/6/2021: pp. 1660, 1667, 1668; Equations: updated font