The Neck Bournemouth Questionnaire, an Item Response Theory Study

Background Several questionnaires on neck pain are usually assumed to be unidimensional as their raw scores are considered interval measures. However, the assumption of unidimensionality requires the questionnaire data to satisfy certain criteria when tested with modern psychometric approaches, such as Item Response Theory. The Neck Bournemouth Questionnaire (NBQ) has already been cross-culturally adapted and validated in Italian on a population of subjects with chronic neck pain (Geri et al., 2014). We examined this scale by means of Rasch analysis an Item Response Theory model in order to provide a disease-specific questionnaire whose scores can be assumed as interval variables and, consequently, legitimately their change scores as meaningful