How well do item parcels represent conceptually defined latent constructs? A two-facet approach

This article presents a methodology for examining the content and nature of item parcels as indicators of a conceptually defined latent construct. An essential component of this methodology is the 2-facet measurement model, which includes items and parcels as facets of construct indicators. The 2-facet model tests assumptions required for accepting parcels as aggregates of item covariation in representing the latent construct. According to this methodology, parcels are acceptable indicators of the latent construct if the 2-facet model meets parametric assumptions for unidimensionality and if items and parcels have content validity as measures of the latent construct. The proposed methodology is illustrated using a 1-factor model of the Worry construct in the test anxiety measurement tradition.