Canadian-French, German and UK versions of the Child Health Questionnaire: methodology and preliminary item scaling results.

Using emerging international guidelines, stringent procedures were used to develop and evaluate Canadian-French, German and UK translations/adaptions of the 50 item, parent-completed Child Health Questionnaire (CHQ-PF50). Multitrait analysis was used to evaluate the convergent and discriminant validity of the hypothesized item sets across countries relative to the results obtained for a representative sample of children in the US. Cronbach's alpha coefficient was used to estimate the internal consistency reliability for each of the health scales. Floor and ceiling effects were also examined. Seventy-nine percent of all the item-scale correlations achieved acceptable internal consistency (0.40 or higher). The tests of the item convergent and discriminant validity were successful at least 87% of the time across all scales and countries. Equal item variance was observed 90% of the time across all countries. The reliability coefficients ranged from a low of 0.43 (parental time impact, Canadian English) to a high of 0.97 (physical functioning index, Canadian French) across all scales (median 0.80). Negligible floor effects were observed across countries. Noteworthy ceiling effects were observed, as expected, for the hypothesized physical scales (mean effect 73%). Conversely, fewer ceiling effects were observed for the psychosocial scales (range 3-17% behaviour-parental emotional impact). The item-scaling results obtained in these pilot studies support the psychometric properties of the American-English CHQ-PF50 and its respective translations.