The International Wealth IndexThis 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.