The International Wealth Index (IWI)

Abstract

This paper presents the International Wealth Index (IWI), the first comparable asset based index of household’s material well-being, or economic status, that can be used for all low and middle income countries. IWI is similar to the widely used wealth indices included in the Demographic and Health Surveys and UNICEF MICS surveys, but adds the property of comparability across place and time. IWI is based on data from 2.1 million households in 97 developing countries. With IWI we provide a stable and understandable yardstick for evaluating and comparing the situation of households, social groups and societies among all regions of the developing world. A household’s ranking on IWI indicates to what extent the household possesses a basic set of assets, valued highly by people across the globe. IWI is tested thoroughly and turns out to be a stable index that hardly depends on the inclusion of specific items or on data for specific regions or time periods. National IWI values are highly correlated with human development, life expectancy, and national income, and IWI-based poverty measures with poverty headcount ratios.

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References

  1. Bollen, K. A., Glanville, J. L., & Stecklov, G. (2002). Economic status proxies in studies of fertility in developing countries: Does the measure matter? Population Studies, 56, 81–96.

    Article  Google Scholar 

  2. Booysen, F., van der Berg, S., Burger, R., von Maltitz, M., & du Rand, G. (2008). Using an asset index to assess trends in poverty in seven sub-saharan African Countries. World Development, 36(6), 1113–1130.

    Article  Google Scholar 

  3. Cordoba, A. (2008). Methodological note: Measuring relative wealth using household asset indicators. Americas Barometer Insights: No. 6. Latin American Public Opinion Project.

  4. Falkingham, J., & Namazi, C. (2002). Measuring health and poverty: A review of approaches to identifying the poor. London: DFID Health Systems Resource Centre.

    Google Scholar 

  5. Filmer, D., & Pritchett, L. (1999). The effect of household wealth on educational attainment: Evidence from 35 countries. Population and Development Review, 25(1), 85–120.

    Article  Google Scholar 

  6. Filmer, D., & Pritchett, L. (2001). Estimating wealth effect without expenditure data-or tears: An application to educational enrollments in states in India. Demography, 38(1), 115–132.

    Google Scholar 

  7. Filmer, D., & Scott, N. (2012). Assessing asset indices. Demography, 49, 359–392.

    Article  Google Scholar 

  8. Guiley, D., & Jayne, S. (1997). Fertility transition in Zimbabwe: determinants of contraceptive use and method choice. Population Studies, 51(2), 173–190.

    Article  Google Scholar 

  9. Gwatkin, D. R., Rutstein, S. Johnson, K., Suliman, E., Wagstaff, A., & Amouzou, A. (2007) Socio-economic differences in health, nutrition, and population within developing countries. HNP, The World Bank.

  10. Howe, L. D., Hargreaves, J. R., Gabrysch, S., & Huttly, Sharon R. A. (2009). Is the wealth index a proxy for consumption expenditure? A systematic review. Journal of Epidemiology and Community Health, 63, 871–880.

    Article  Google Scholar 

  11. Howe, L. D., Hargreaves, J. R., & Huttly, Sharon R. A. (2008). Issues in the construction of wealth indices for the measurement of socio-economic position in low-income countries. Emerging Themes in Epidemiology, 5, 3.

    Article  Google Scholar 

  12. McKenzie, D. J. (2005). Measuring inequality with asset indicators. Journal of Population Economics, 18, 229–260.

    Article  Google Scholar 

  13. Montgomery, M., Gragnolati, M., Burke, K., & Paredes, E. (2000). Measuring living standards with proxy variables. Demography, 37, 155–174.

    Article  Google Scholar 

  14. Rutstein, S. O. (2008). The DHS Wealth Index: Approaches for rural and urban areas. DHS working paper, 2008, 60, Measure DHS.

  15. Rutstein, S. & Johnson, K. (2004) The DHS Wealth Index, DHS Comparative Report, No. 6, ORC Macro, Calverton, MD.

  16. Sahn, D. E., & Stifel, D. C. (2000). Poverty comparisons over time and across countries in Africa. World Development, 28(12), 2123–2155.

    Article  Google Scholar 

  17. Sahn, D. E., & Stifel, D. C. (2003). Exploring alternative measures of welfare in the absence of expenditure data. Review of Income and Wealth, 49(4), 463–489.

    Article  Google Scholar 

  18. Stanton, E. (2006). Accounting for Inequality: A proposed revision of the Human Development Index. PERI working paper 119. Amherst: Political Economy Research Institute.

  19. UNDP. (2011). Human development report 2011. New York: United Nations Development Programme.

    Google Scholar 

  20. Vyas, S., & Kumaranayake, L. (2006). Constructing socio-economic status indices: how to use principal components analysis. Oxford: Oxford University Press. doi:10.1093/heapol/czl029.

    Google Scholar 

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Acknowledgments

We are grateful to the DHS Program, the UNICEF MICS department, the Pan Arabic Project for Family Health (PAPFAM), the Integrated Public Use Microdata Series (IPUMS) department of the Minnesota Population Center, the National Statistical Offices of Brazil, Chile, Costa Rica, Sudan, Uruguay and Venezuela, the Statistical Information and Monitoring Programme on Child Labour (SIMPOC) of ILO-IPEC, and the Carolina Population Center at the University of North Carolina at Chapel Hill for making the datasets available that have been used in this project.

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Correspondence to Jeroen Smits.

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Smits, J., Steendijk, R. The International Wealth Index (IWI). Soc Indic Res 122, 65–85 (2015). https://doi.org/10.1007/s11205-014-0683-x

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Keywords

  • Comparable wealth index
  • Assets
  • Developing world
  • Material well-being
  • Welfare measurement
  • Poverty measurement