Discrepancies in the Country Versions of the WHOQOL-BREF as a Potential Source of Error in Assessing Quality of Life and a Barrier to Comparative Research

The WHOQOL-BREF questionnaire is widely used globally in research that requires the assessment of quality of life. Its official status, broad availability in multiple languages, and the fact that it is free to use are the primary reasons it is selected by researchers and clinicians. However, the quality of particular language versions and the lack of standardization raise concerns about the quality of data collected in different countries and thus their comparability. In this study, 17 country versions published on the WHO website were analyzed. Each translation was compared to the model English questionnaire in terms of visual layout, inclusion of instructions for respondents, timeframe of measurement, and additional elements. Moreover, selected versions were reviewed by native speakers and with use of LLM to assess the accuracy of the question and scale translations. The results of the analysis revealed significant discrepancies between translations in all analyzed fields. Some translation errors were so severe that responses to certain questions could not be meaningfully compared. The study concludes that the WHOQOL-BREF questionnaire translations should be reviewed across all evaluated elements to ensure its consistency and comparability. Additionally, specific language versions developed by various academic institutions should be closely scrutinized by the WHO team. A common practice of adding a note that a particular version is not an official WHO translation will not suffice, as these tools are treated de facto as officially approved by researchers and medical specialists.