Development Economics Data Group, The World Bank
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Food security, Education economics, Health economics, Data collection methods, Measuring Poverty
Development Economics Data Group, The World Bank
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Last updated August 29, 2023
Dean Jolliffe is a lead economist in the Development Data Group at the World Bank. He is a member of the Living Standards Measurement Study team and co-lead of the team that works on global poverty measurement (PovcalNet). Previously, he worked in the Research Group and the South Asia region of the World Bank. Prior to joining the World Bank, he was a research economist with the Economic Research Service of the U.S. Department of Agriculture, an assistant professor at Charles University Center for Economic Research and Graduate Education in Prague, an adjunct professor at Johns Hopkins University School of Advanced International Studies, an adjunct professor at Georgetown University Public Policy Institute, and a postdoctoral fellow at the International Food Policy Research Institute. Dean holds appointments as a research fellow with the Institute for the Study of Labor, as a co-opted council member of the International Association for Research in Income and Wealth, and as a fellow of the Global Labor Organization. He received his PhD in economics from Princeton University.
Publication Search Results
Now showing 1 - 10 of 13
Publication(World Bank, Washington, DC, 2015-07) Jolliffe, Dean ; Serajuddin, UmarPoverty estimates based on enumeration from a single point in time form the cornerstone for much of the literature on poverty. Households are typically interviewed once about their consumption or income, and their wellbeing is assessed from their responses. Global estimates of poverty that aggregate poverty counts from all countries implicitly assume that the counts are comparable. This paper illustrates that this assumption of comparability is potentially invalid when households are interviewed multiple times with repeat visits throughout the year. The paper provides an example from Jordan, where the internationally comparable approach of handling the data from repeat visits yields a poverty rate that is 26 percent greater than the rate that is currently reported as the official estimate. The paper also explores alternative definitions of poverty, informed in part by the psychological and biophysical literature on the long-run effects of short-term exposure to poverty or generally adverse environments. This alternative concept of poverty suggests that the prevalence of those who have been affected by poverty in Jordan during 2010 is more than twice as large as the official 2010 estimate of poverty.
Publication(World Bank, Washington, DC, 2015-10) Ferreira, Francisco H. G. ; Chen, Shaohua ; Dabalen, Andrew ; Dikhanov, Yuri ; Hamadeh, Nada ; Jolliffe, Dean ; Narayan, Ambar ; Prydz, Espen Beer ; Revenga, Ana ; Sangraula, Prem ; Serajuddin, Umar ; Yoshida, NobuoThe 2014 release of a new set of purchasing power parity conversion factors (PPPs) for 2011 has prompted a revision of the international poverty line. In order to preserve the integrity of the goalposts for international targets such as the Sustainable Development Goals and the World Bank’s twin goals, the new poverty line was chosen so as to preserve the definition and real purchasing power of the earlier $1.25 line (in 2005 PPPs) in poor countries. Using the new 2011 PPPs, the new line equals $1.90 per person per day. The higher value of the line in US dollars reflects the fact that the new PPPs yield a relatively lower purchasing power of that currency vis-à-vis those of most poor countries. Because the line was designed to preserve real purchasing power in poor countries, the revisions lead to relatively small changes in global poverty incidence: from 14.5 percent in the old method to 14.1 percent in the new method for 2011. In 2012, the new reference year for the global count, we find 12.7 percent of the world’s population, or 897 million people, are living in extreme poverty. There are changes in the regional composition of poverty, but they are also relatively small. This paper documents the detailed methodological decisions taken in the process of updating both the poverty line and the consumption and income distributions at the country level, including issues of inter-temporal and spatial price adjustments. It also describes various caveats, limitations, perils and pitfalls of the approach taken.
Publication(World Bank, Washington, DC, 2015-05) Jolliffe, Dean Mitchell ; Prydz, Espen BeerWith the recent release of the 2011 purchasing power parity (PPP) data from the International Comparison Program (ICP), analysts and institutions are confronted with the question of whether and how to use them for global poverty estimation. The previous round of PPP data from 2005 led to a large increase in the estimated number of poor in the world. The 2011 price data suggest that developing countries’ incomes in PPP-adjusted dollars are significantly higher than indicated by the 2005 PPP data. This has created the anticipation that the new PPP data will decrease significantly the count of poor people in the world. This paper presents evidence that if the global poverty line is updated with the 2011 PPP data based on the same set of national poverty lines that define the $1.25 line in 2005 PPPs, and if the 2011 PPP conversion factors are used without adjustments to selected countries, the 2011 poverty rate is within half a percentage point of the current global estimate based on 2005 PPPs. The analysis also indicates that the goal of ‘ending’ extreme poverty by 2030 continues to be an ambitious one.
Publication(World Bank, Washington, DC, 2015-12-08) Yaacoub, Najwa ; Daher, Mayssaa ; Jolliffe, Dean ; Atamanov, AzizThis brief is based on analysis of the 2011-12 household budget survey (HBS) implemented by Central Administration for Statistics (CAS) with technical assistance from the World Bank. The survey was conducted during the period of September 2011 to November 2012, and was stratified across nine regions. The sample was designed to cover 4,805 households, but due to high non-response, it only includes 2,476 participating households. Poverty numbers presented in this note are not comparable with poverty estimates for other years due to differences in the instruments, fieldwork implementation and to some extent sample design; and also due to differences in the methodology for constructing welfare aggregate and the poverty line. All regional estimates in this report should be viewed with caution given concerns about significant levels of nonresponse and relatively small sample sizes within regions. CAS and the World Bank are working together to improve the quality of future surveys.
Publication(Washington, DC, 2016-03) Jolliffe, Dean ; Prydz, Espen BeerWorld Bank's international poverty line of $1.90/day, at 2011 purchasing power parity, is based on a collection of national poverty lines, which were originally used to set the international poverty line of $1.25/day at 2005 purchasing power parity. This paper proposes an approach for estimating a more recent, complete, and comparable collection of national poverty thresholds from reported national poverty rates. The paper presents a set of international poverty lines based on this new database of national poverty lines. In contrast to the lines used to estimate the $1.90 international poverty line, this approach produces national poverty lines that are (1) consistent with national poverty rates, (2) expressed in common units, and (3) provide greater support to the estimated international poverty line. These national poverty lines are used to estimate an extreme international poverty line, and three higher lines that are more relevant for higher-income countries. A key finding provides evidence of the robustness and relevance of the $1.90 international poverty line as a measure of extreme poverty for low-income countries.
Publication(World Bank, Washington, DC, 2019-09) Atamanov, Aziz ; Castaneda Aguilar, R. Andres ; Diaz-Bonilla, Carolina ; Jolliffe, Dean ; Lakner, Christoph ; Mahler, Daniel Gerszon ; Montes, Jose ; Moreno Herrera, Laura Liliana ; Newhouse, David ; Nguyen, Minh C. ; Prydz, Espen Beer ; Sangraula, Prem ; Tandon, Sharad Alan ; Yang, JudyThe September 2019 global poverty update from the World Bank includes revised survey data which lead to minor changes in the most recent global poverty estimates. The update includes revisions to 18 surveys from four countries. As a result of the revised data, the estimate of the global 1.90 US Dollars headcount ratio for 2015 increases slightly from 9.94 percent to 9.98 percent, whereas the number of poor increases from 731.0 million to 734.5 million people.
Publication(World Bank, Washington, DC, 2022-10) Jolliffe, Dean ; Tetteh Baah, Samuel KofiEstimates of the number of people living in extreme poverty, as reported by the World Bank, figure prominently in international development dialogue and policy. An assumption underpinning these poverty counts is that there are no economies of scale in household size—a family of six needs three times as much as a family of two. This paper examines the sensitivity of global estimates of extreme poverty to changing this assumption. The analysis rests on nationally representative household surveys from 162 countries covering 98 percent of the population estimated to be in extreme poverty in 2017. The paper compares current-method estimates with a constant-elasticity scale adjustment that divides total household consumption or income not by household size but by the square root of household size. While the regional profile of extreme poverty is robust to this change, the determination of who is poor changes substantially—the poverty status of 270 million people changes. The paper then shows that the measure that accounts for economies of scale is significantly more correlated with a set of presumed poverty covariates (years of schooling, literacy, asset index, working in agriculture, access to electricity, piped drinking water, and improved sanitation).
Publication(World Bank, Washington, DC, 2020-03) Atamanov, Aziz ; Castaneda Aguilar, R. Andres ; Fujs, Tony H.M.J. ; Dewina, Reno ; Diaz-Bonilla, Carolina ; Mahler, Daniel Gerszon ; Jolliffe, Dean ; Lakner, Christoph ; Matytsin, Mikhail ; Montes, Jose ; Moreno Herrera, Laura L. ; Mungai, Rose ; Newhouse, David ; Nguyen, Minh C. ; Parada Gomez Urquiza, Francisco J. ; Silwal, Ani Rudra ; Sanchez Castro, Diana M. ; Schoch, Marta ; Vargas Mogollon, David L. ; Viveros Mendoza, Martha C. ; Yang, Judy ; Yoshida, Nobuo ; Wu, HaoyuThe March 2020 update to PovcalNet involves several changes to the data underlying the global poverty estimates. Some welfare aggregates have been changed for improved harmonization, and some of the CPI, national accounts, and population input data have been revised. This document explains these changes in detail and the reasoning behind them. In addition to the changes listed here, a large number of new country-years have been added, bringing the total number of surveys to more than 1,900.
Publication(World Bank, Washington, DC, 2017-05) Jolliffe, Dean ; Prydz, Espen BeerPoverty lines are typically higher in richer countries, and lower in poorer ones, reflecting the relative nature of national assessments of who is considered poor. In many high-income countries, poverty lines are explicitly relative, set as a share of mean or median income. Despite systematic variation in how countries define poverty, global poverty counts are based on fixed-value lines. To reflect national assessments of poverty in a global headcount of poverty, this paper proposes a societal poverty line. The proposed societal poverty line is derived from 699 harmonized national poverty lines, and has an intercept of $1 per day and a relative gradient of 50 percent of median national income or consumption. The societal poverty line is more closely aligned with national definitions of poverty than other proposed relative lines. By this relative measure, societal poverty has fallen steadily since 1990, but at a much slower pace than absolute extreme poverty.
Publication(Taylor and Francis, 2017-01-23) Jolliffe, Dean ; Serajuddin, UmarPoverty estimates based on enumeration from a single point in time form the basis for most country-level analysis of poverty. Cross-country comparisons of poverty, and global counts of the poor, implicitly assume that country-level poverty headcounts are comparable. This paper illustrates that the assumption of comparability is potentially invalid when households are interviewed multiple times throughout the year, as opposed to a single-visit interview. An example from Jordan illustrates how the internationally comparable approach of handling data from repeat visits yields a poverty rate that is 26 per cent greater than the rate that is currently reported as the official estimate.