PEDIATRIC RHEUMATOLOGY, cilt.8, 2010 (SCI-Expanded)
Background: The original version of the Childhood Health Assessment Questionnaire (CHAQ30orig) suffers from a ceiling effect and hence has reduced clinical validity. The purpose of this study was to evaluate the effect of adding eight more demanding items (CHAQ38) and a new categorical response option (CATII) on discriminant validity and score distribution in a European patient sample.