Partial Measurement Invariance

Measurement invariance, also referred to as measurement equivalence or lack of differential item functioning, is a term used to describe a property of an instrument (e.g., test, survey, or questionnaire) that measures a latent construct with observed indicators. Full measurement invariance signifies that all of the parameters that determine the empirical relations between the indicators and the construct are equal for any given measurement condition (e.g., different time points or groups) and that the relations are not condition-specific. If full measurement invariance is achieved, then the differences in subjects’ observed scores are due to differences in the latent construct rather than a condition-specific variable that systematically influences the responses. It is required whenever researchers use a measure’s observed composite scores to compare conditions (e.g., pre- ...