Development and validation of the interview version of the Hong Kong Chinese WHOQOL-BREF

Introduction. The Hong Kong Chinese version of the WHOQOL-BREF was designed as a self-administered questionnaire and has limitations in clinical application on subjects who have limitations in reading or writing. An interview version is therefore needed to avoid sampling biases in clinical studies. Since there are significant differences in the written Chinese and spoken Cantonese, which is a dialect commonly spoken among people in Hong Kong, and adaptation process for converting the written Chinese into spoken Cantonese was necessary. The interview version was designed to allow administration in both face-to-face interview and telephone interview mode. Methods. Three members of the research team translated the formal written Chinese in the self-administered version of the WHOQOL-BREF(HK) into colloquial Cantonese separately. Brief notes extracted from the facet definitions of the WHOQOL-100 were added in brackets after some questions to further explain the intention of the questions. Two series of focus groups were conducted and subsequently the field test version was produced. 329 subjects were recruited by convenient sampling method for the field test. Results. The interview version and the self-administered version was found equivalent. The ICC values of the domain scores ranged from 0.73 in the environment domain to 0.83 in the psychological domain. The face-to-face interview and telephone interview mode of administration were also found equivalent. The ICC for the domain scores ranged from 0.76 in the social interaction domain to 0.84 in the psychological domain. The other psychometric properties of the interview version were found comparable to the self-administered version. Conclusion. The self-administered and the interview version of the WHOQOL-BREF are regarded as identical in group comparison. The authors advise that it is acceptable to use different versions on different subjects in the same study, provided that the same version is applied on the same subject throughout the study.