Comparative analyses of more than 50 household surveys on health status

The objective of this study is to determine whether existing data sources from household interview based surveys conducted in a large number of countries may be used towards estimating the distribution and levels of severity of non-fatal health at the population level. Operationally, this objective addresses two main questions: 1. Is there information content on the severity and distribution of non-fatal health status in data collected through household interview surveys? 2. May this information be compared in a valid and reliable manner across countries? The paper first reviews current approaches to measure health status within interview based surveys and the limitations of these approaches concerning the cross-population comparability of data collected, not only the comparability of questions. Issues demanding further attention concerning the cross-population comparability include inconsistent reporting and differences in end-points and cut-points on reference scales. These limitations prevent the meaningful comparison of survey data within and across populations. The paper then describes and tests a methodology to extract information on non-fatal health status. This approach is specific to self-reported data from different surveys conducted in different populations, as a first attempt to improve comparability of data given that no external means to calibrate responses are available. Sixty four data sets from an array of surveys in 46 countries are analyzed using factor analysis, based on the hypothesis that one underlying latent construct, non-fatal health, is similar across surveys and populations. A factor score of the level of non-fatal health is estimated for each individual and all scores are re-scaled within each population to improve comparability of end-points. Results are provided by age groups and sex, for data from each of the 46 countries included in this study. Based on an examination of the results within countries, the evidence concerning the information content of surveys is mixed. Despite efforts to improve the comparability of existing household interview data on non-fatal health, the paper concludes that the valid comparison of existing data from household interview surveys across countries is limited. Even where the survey methodologies and data collection approaches are standardized, biases in the self-report of health status prevent a meaningful comparison of non-fatal health status across populations. These results are disappointing given that a growing number of countries carry out household interview surveys addressing health topics, coupled with the WHO mandate to improve the use and comparability of existing data on non-fatal health. Yet WHO realizes that household interview based surveys are considerably less expensive to conduct than household examination surveys, and that countries will continue to utilize data collected within household interview surveys as one input to estimate the distribution and levels of severity of non-fatal health, among other objectives. Given these realistic constraints and objectives, this paper ends with a discussion of selected strategies to improve the cross-population comparability of self-reported data on non-fatal health.

• http://cdrwww.who.int/healthinfo/paper15.pdf