Fig. 2

Hypothesized Continuum of Sensitivity to Response-Shift Effects. We posit that there is a continuum of measurement sensitivity to response-shift effects, with the least sensitive being measures developed using IRT methods with the intention of developing a specific and unidimensional measure of a construct (IRT single-domain measures). Measures hypothesized to be most sensitive to response-shift effects would be developed with a focus on alpha reliability and construct validity that follow logical arguments but have relatively fewer quantitative metrics of model fit and item function than IRT (CTT-based measures). In between these two extremes are measures that use IRT methods for calibration and item selection but which seek to be general tools for measuring QOL rather than measures of unidimensional constructs of domains (IRT multiple-domain measures).