Assessing construct structural validity of epidemiological measurement tools: a seven-step roadmap

Abstract

Guidelines have been proposed for assessing the quality of clinical trials, observational studies and validation studies of diagnostic tests. More recently, the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) initiative extended those in regards to epidemiological measurement tools in general. Among various facets proposed for assessment is the validity of an instrument's dimensional structure (or structural validity). The purpose of this article is to extend these guidelines. A seven-step roadmap is proposed to examine (1) the hypothesized dimensional structure; (2) strength of component indicators regarding loading patterns and measurement errors; (3) measurement error correlations; (4) factor-based convergent and discriminant validity of scales; (5) item discrimination and intensity vis-à-vis the latent trait spectrum; and (6) the properties of raw scores; and (7) factorial invariance. The paper also holds that the suggested steps still require debate and are open to refinements.