For the purpose of this study, we utilize data from as many as 89 countries for which a nationally representative welfare survey from 2009 or later was conducted and obtained by the World Bank, and for which 2013 poverty rates have been published.<sup>10,11</sup> Figure 1 presents the number of surveys in the final sample, according to their survey year. The final sample contains 104 surveys. In 15 of the 89 countries there are two available surveys bracketing 2013, which are both utilized as described below. The year 2009 was selected as the cut-off year to balance the competing goals of maximizing geographical coverage of the sample and minimizing error when “lining up”, or extrapolating, country-level poverty figures to 2013 as discussed in Section 2.2.

**Figure 1: Number of surveys by survey year**

<!-- Start of picture text --> 15 10<br>15<br>2009 2010<br>24 2011 2012<br>10<br>30 2013 2014<br><!-- End of picture text --> In total, the 89 countries in the sample used in this paper represent 84% of the developing world’s population in 2013 and all geographical regions (Figure 2).<sup>12</sup> The 650 million in the sample that are classified as extremely poor amount to 85.4% of the estimated number of extreme poor worldwide in 2013, according to the World Bank.<sup>13</sup> Table 1 lists the number of countries and the share of the 2013 population represented in the sample, by region and income classification. Except for the Middle East and North Africa (MENA) and Sub-Saharan Africa (SSA) regions, the sample used in this study provides excellent coverage of the global population and the extreme poor. While the extremely low data coverage in the MENA region is a concern, it is not unique to this study. In fact, PovcalNet has for several years suppressed regional poverty estimates for the MENA region due to low survey coverage. But since the region has traditionally had a much lower incidence of poverty than the average for global and developing countries, the omission of most countries from the region has a limited impact on the characteristics of the poor.<sup>14</sup> The omission of over one-quarter of the population of Sub-Saharan Africa is a greater concern, since the region has the highest number of extreme poor (389 million)

> 10 In order to maintain consistency with the figures reported by the World Bank, we only include countries classified as “developing countries”. This excludes most of Western Europe, Canada, the United States, Australia, Japan, and the Republic of Korea.

> 11 Not every survey is fully nationally representative, due to the exclusion of rural areas or conflict areas in particular countries.

> 12 Population figures are based on population projections by the United Nations Department of Economic and Social Affairs (UNDESA).

> 13 Global poverty estimates are available on PovcalNet (http://iresearch.worldbank.org/PovcalNet). We refer to PovcalNet as a key reference point to assess the extent of our sample coverage and the validity of our estimates. As shown in Figure 1, our sample includes almost all countries covered by PovcalNet.

> 14 In 2008, the most recent year MNA estimates are reported, the region accounted for 0.7 percent of the total number of extreme poor.

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