Purpose The minimal detectable change (MDC) of questionnaire ordinal scores (MDCord) is the smallest score difference exceeding the measurement error. Being ordinal, it suffers from flaws, successfully addressed by the Rasch analysis (RA) and its robust interval measures. However, RA measures struggle to become established, likely because scores are more straightforward. This study aims to derive the MDCord of two upper limb measures, the Fugl-Meyer Assessment-Upper Limb (FMA-UL) and the Functional Assessment Test for Upper Limb (FAST-UL), from the MDC of their RA interval measures (MDCint).
Caronni et al. (Fri,) studied this question.