Rasch model of the Child Perceptions Questionnaire for oral health-related quality of life A step forward toward accurate outcome measures

Background. Oral health is related to major chronic diseases and contributes to general health. Oral health-related quality of life (OHRQoL) is, therefore, an essential part of well-being. Measurement of OHRQoL over the lifetime requires accurate and comparable outcome measures that are suitable for different age groups. The most frequently used instrument for children aged 11 through 14 years is the Child Perceptions Questionnaire (CPQ-11-14). The authors aimed to examine the psychometric properties of the CPQ-11-14 using modern statistical approaches. Methods. The authors carried out a psychometric analysis of 2 population-representative data sets from Germany (N = 2,658) and a randomly selected smaller sample (n = 300) on the basis of the Rasch model. Results. The authors detected a right-skewed distribution of the CPQ-11-14 total scores. The instrument items did not match the level of OHRQoL of the study participants. Moreover, a large number of questionnaire items (range, 51.4%-94.3%) had so-called disordered thresholds, meaning that the answer categories did not work as intended. Unidimensionality was achieved via splitting the CPQ-11-14 into 2 subscales, namely socioemotional and oral symptoms and functioning. Conclusions. Despite its classic validation, the CPQ-11-14 needs adaptions for meaningful clinical use. More items on the better end of the scale are needed to better differentiate between children with higher and lower OHRQoL. Practical Implications. The Rasch model addresses psychometric properties of questionnaires on an item-based level, which were not detected via classic approaches. The results reported by the authors are needed to generate a well-calibrated outcome measure for accurate clinical and public health assessment of OHRQoL.