Publication: Identifying the Poor: Accounting for Household Economies of Scale in Global Poverty Estimates
Loading...
Date
2022-10
ISSN
Published
2022-10
Author(s)
Tetteh Baah, Samuel Kofi
Editor(s)
Abstract
Estimates 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).
Link to Data Set
Citation
“Tetteh Baah, Samuel Kofi; Jolliffe, Dean. 2022. Identifying the Poor: Accounting for Household Economies of Scale in Global Poverty Estimates. Policy Research Working Papers;10209. © World Bank. http://hdl.handle.net/10986/38179 License: CC BY 3.0 IGO.”
Associated URLs
Associated content
Other publications in this report series
Publication Geopolitics and the World Trading System(Washington, DC: World Bank, 2024-12-23)Until the beginning of this century, the GATT/WTO system worked. Economic research provided a compelling explanation. It showed that if governments maximize the well-being of their own countries broadly defined, GATT/WTO principles would facilitate mutually beneficial cooperation over their trade policy choices. Now heightened geopolitical rivalry seems to have undermined the WTO. A simple transposition of the previous rationalization suggests that geopolitics and trade cooperation are not compatible. The paper shows that this is only true if rivalry eclipses any consideration of own-country well-being. In all other circumstances, there are gains from trade cooperation even with geopolitics. Furthermore, the WTO’s relevance is in question only if it adheres too rigidly to its existing rules and norms. Through measured adaptation to the geopolitical imperative, the WTO can continue to thrive as a forum for multilateral trade cooperation in the age of geopolitics.Publication The Macroeconomic Implications of Climate Change Impacts and Adaptation Options(Washington, DC: World Bank, 2025-05-29)Estimating the macroeconomic implications of climate change impacts and adaptation options is a topic of intense research. This paper presents a framework in the World Bank's macrostructural model to assess climate-related damages. This approach has been used in many Country Climate and Development Reports, a World Bank diagnostic that identifies priorities to ensure continued development in spite of climate change and climate policy objectives. The methodology captures a set of impact channels through which climate change affects the economy by (1) connecting a set of biophysical models to the macroeconomic model and (2) exploring a set of development and climate scenarios. The paper summarizes the results for five countries, highlighting the sources and magnitudes of their vulnerability --- with estimated gross domestic product losses in 2050 exceeding 10 percent of gross domestic product in some countries and scenarios, although only a small set of impact channels is included. The paper also presents estimates of the macroeconomic gains from sector-level adaptation interventions, considering their upfront costs and avoided climate impacts and finding significant net gross domestic product gains from adaptation opportunities identified in the Country Climate and Development Reports. Finally, the paper discusses the limits of current modeling approaches, and their complementarity with empirical approaches based on historical data series. The integrated modeling approach proposed in this paper can inform policymakers as they make proactive decisions on climate change adaptation and resilience.Publication Global Poverty Revisited Using 2021 PPPs and New Data on Consumption(Washington, DC: World Bank, 2025-06-05)Recent improvements in survey methodologies have increased measured consumption in many low- and lower-middle-income countries that now collect a more comprehensive measure of household consumption. Faced with such methodological changes, countries have frequently revised upward their national poverty lines to make them appropriate for the new measures of consumption. This in turn affects the World Bank’s global poverty lines when they are periodically revised. The international poverty line, which is based on the typical poverty line in low-income countries, increases by around 40 percent to $3.00 when the more recent national poverty lines as well as the 2021 purchasing power parities are incorporated. The net impact of the changes in international prices, the poverty line, and new survey data (including new data for India) is an increase in global extreme poverty by some 125 million people in 2022, and a significant shift of poverty away from South Asia and toward Sub-Saharan Africa. The changes at higher poverty lines, which are more relevant to middle-income countries, are mixed.Publication From Patriarchy to Policy(Washington, DC: World Bank, 2025-05-29)Legal institutions play an important role in shaping gender equality in economic domains, from inheritance to labor markets. But where do gender equal laws come from? Using cross-country data on social norms and legal equality, this paper investigates the socio-cultural roots of gender inequity in the legal system and its implications for female labor force participation. To identify the impact of social norms, the analysis uses an empirical strategy that exploits pre-modern differences in ancestral patriarchal culture as an instrument for present-day gender norms. The findings show that ancestral patriarchal culture is a strong predictor of contemporary norms, and conservative social norms are associated with more gender inequality in the de jure legal framework, the de facto implementation of laws, and the labor market. The paper presents evidence for a political selection mechanism linking norms to laws: countries with more conservative norms elect political leaders who are more hostile to gender equality, who then pass less progressive legislation. The results highlight the cultural roots and political drivers of legalized gender inequality.Publication Global Socio-economic Resilience to Natural Disasters(Washington, DC: World Bank, 2025-05-22)Most disaster risk assessments use damages to physical assets as their central metric, often neglecting distributional impacts and the coping and recovery capacity of affected people. To address this shortcoming, the concepts of well-being losses and socio-economic resilience—the ability to experience asset losses without a decline in well-being—have been proposed. This paper uses microsimulations to produce a global estimate of well-being losses from, and socio-economic resilience to, natural disasters, covering 132 countries. On average, each $1 in disaster-related asset losses results in well-being losses equivalent to a $2 uniform national drop in consumption, with significant variation within and across countries. The poorest income quintile within each country incurs only 9% of national asset losses but accounts for 33% of well-being losses. Compared to high-income countries, low-income countries experience 67% greater well-being losses per dollar of asset losses and require 56% more time to recover. Socio-economic resilience is uncorrelated with exposure or vulnerability to natural hazards. However, a 10 percent increase in GDP per capita is associated with a 0.9 percentage point gain in resilience, but this benefit arises indirectly—such as through higher rate of formal employment, better financial inclusion, and broader social protection coverage—rather than from higher income itself. This paper assess ten policy options and finds that socio-economic and financial interventions (such as insurance and social protection) can effectively complement asset-focused measures (e.g., construction standards) and that interventions targeting low-income populations usually have higher returns in terms of avoided well-being losses per dollar invested.
Journal
Journal Volume
Journal Issue
Collections
Related items
Showing items related by metadata.
Publication Identifying the poor – Accounting for household economies of scale in global poverty estimates(Elsevier, 2024-03-30)Estimates 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 97.5 percent of the population estimated to be in extreme poverty in 2019. We compare 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 264 million people changes. We then discuss evidence suggesting that the assumption of economies of scale more closely aligns with non-consumption measures of poverty. Specifically, we draw from existing literature of subjective assessments of poverty and wellbeing, along with new empirical evidence from examining the partial correlation (conditional on household size) between the two measures of poverty and a set of presumed poverty covariates (i.e., years of schooling, literacy, asset index, working in agriculture, access to electricity, piped drinking water, improved sanitation).Publication September 2020 PovcalNet Update(World Bank, Washington, DC, 2020-09)The September 2020 update to PovcalNet mainly involves the adoption of the revised 2011 PPPs for the estimation of global poverty. In addition, the coverage rules for reporting regional and global poverty aggregates have been reviewed, resulting in small adjustments. Historical regional and global aggregates are now reported with an annual frequency instead of intervals with varying lengths. Only two surveys have been added and some welfare aggregates have been revised compared with the March 2020 update. National accounts and population input data have been updated. This document explains these changes and the rationale behind them in detail. The data and associated estimates are used for the analysis of global poverty in the forthcoming Poverty and Shared Prosperity Report 2020.Publication A Global Count of the Extreme Poor in 2012(World Bank, Washington, DC, 2015-10)The 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 Assessing the Impact of the 2017 PPPs on the International Poverty Line and Global Poverty(Washington, DC: World Bank, 2022-02-21)Purchasing power parity exchange rates (PPPs) are used to estimate the international poverty line (IPL) in a common currency and account for relative price differences across countries when measuring global poverty. This paper assesses the impact of the 2017 PPPs on the nominal value of the IPL and global poverty. The analysis indicates that updating the $1.90 IPL in 2011 PPP dollars to 2017 PPP dollars results in an IPL of approximately $2.15—a finding that is robust to various methods and assumptions. Based on an updated IPL of $2.15, the global extreme poverty rate in 2017 falls from the previously estimated 9.3 to 9.1 percent, reducing the count of people who are poor by 15 million. This is a modest change compared with previous updates of PPP data. The paper also assesses the methodological stability between the 2011 and 2017 PPPs, scrutinizes large changes at the country level, and analyzes higher poverty lines with the 2017 PPPs.Publication April 2022 Update to the Poverty and Inequality Platform (PIP)(World Bank, Washington, DC, 2022-04)The April 2022 update to the newly launched Poverty and Inequality Platform (PIP) involves several changes to the data underlying the global poverty estimates. Some welfare aggregates have been changed for improved harmonization, and the CPI, national accounts, and population input data have been updated. This document explains these changes in detail and the reasoning behind them. Moreover, a large number of new country-years have been added, bringing the total number of surveys to more than 2,000. These include new harmonized surveys for countries in West Africa, new imputed poverty estimates for Nigeria, and recent 2020 household survey data for several countries. Global poverty estimates are now reported up to 2018 and earlier years have been revised.
Users also downloaded
Showing related downloaded files
Publication South Asia Development Update, April 2024: Jobs for Resilience(Washington, DC: World Bank, 2024-04-02)South Asia is expected to continue to be the fastest-growing emerging market and developing economy (EMDE) region over the next two years. This is largely thanks to robust growth in India, but growth is also expected to pick up in most other South Asian economies. However, growth in the near-term is more reliant on the public sector than elsewhere, whereas private investment, in particular, continues to be weak. Efforts to rein in elevated debt, borrowing costs, and fiscal deficits may eventually weigh on growth and limit governments' ability to respond to increasingly frequent climate shocks. Yet, the provision of public goods is among the most effective strategies for climate adaptation. This is especially the case for households and farms, which tend to rely on shifting their efforts to non-agricultural jobs. These strategies are less effective forms of climate adaptation, in part because opportunities to move out of agriculture are limited by the region’s below-average employment ratios in the non-agricultural sector and for women. Because employment growth is falling short of working-age population growth, the region fails to fully capitalize on its demographic dividend. Vibrant, competitive firms are key to unlocking the demographic dividend, robust private investment, and workers’ ability to move out of agriculture. A range of policies could spur firm growth, including improved business climates and institutions, the removal of financial sector restrictions, and greater openness to trade and capital flows.Publication Economic Recovery(World Bank, Washington, DC, 2021-04-06)World Bank Group President David Malpass spoke about the world facing major challenges, including COVID, climate change, rising poverty and inequality and growing fragility and violence in many countries. He highlighted vaccines, working closely with Gavi, WHO, and UNICEF, the World Bank has conducted over one hundred capacity assessments, many even more before vaccines were available. The World Bank Group worked to achieve a debt service suspension initiative and increased transparency in debt contracts at developing countries. The World Bank Group is finalizing a new climate change action plan, which includes a big step up in financing, building on their record climate financing over the past two years. He noted big challenges to bring all together to achieve GRID: green, resilient, and inclusive development. Janet Yellen, U.S. Secretary of the Treasury, mentioned focusing on vulnerable people during the pandemic. Kristalina Georgieva, Managing Director of the International Monetary Fund, focused on giving everyone a fair shot during a sustainable recovery. All three commented on the importance of tackling climate change.Publication Remarks at the United Nations Biodiversity Conference(World Bank, Washington, DC, 2021-10-12)World Bank Group President David Malpass discussed biodiversity and climate change being closely interlinked, with terrestrial and marine ecosystems serving as critically important carbon sinks. At the same time climate change acts as a direct driver of biodiversity and ecosystem services loss. The World Bank has financed biodiversity conservation around the world, including over 116 million hectares of Marine and Coastal Protected Areas, 10 million hectares of Terrestrial Protected Areas, and over 300 protected habitats, biological buffer zones and reserves. The COVID pandemic, biodiversity loss, climate change are all reminders of how connected we are. The recovery from this pandemic is an opportunity to put in place more effective policies, institutions, and resources to address biodiversity loss.Publication The Journey Ahead(Washington, DC: World Bank, 2024-10-31)The Journey Ahead: Supporting Successful Migration in Europe and Central Asia provides an in-depth analysis of international migration in Europe and Central Asia (ECA) and the implications for policy making. By identifying challenges and opportunities associated with migration in the region, it aims to inform a more nuanced, evidencebased debate on the costs and benefits of cross-border mobility. Using data-driven insights and new analysis, the report shows that migration has been an engine of prosperity and has helped address some of ECA’s demographic and socioeconomic disparities. Yet, migration’s full economic potential remains untapped. The report identifies multiple barriers keeping migration from achieving its full potential. Crucially, it argues that policies in both origin and destination countries can help maximize the development impacts of migration and effectively manage the economic, social, and political costs. Drawing from a wide range of literature, country experiences, and novel analysis, The Journey Ahead presents actionable policy options to enhance the benefits of migration for destination and origin countries and migrants themselves. Some measures can be taken unilaterally by countries, whereas others require close bilateral or regional coordination. The recommendations are tailored to different types of migration— forced displacement as well as high-skilled and low-skilled economic migration—and from the perspectives of both sending and receiving countries. This report serves as a comprehensive resource for governments, development partners, and other stakeholders throughout Europe and Central Asia, where the richness and diversity of migration experiences provide valuable insights for policy makers in other regions of the world.Publication Media and Messages for Nutrition and Health(World Bank, Washington, DC, 2020-06)The Lao People’s Democratic Republic (Lao PDR) has experienced rapid and significant economic growth over the past decade. However, poor nutritional outcomes remain a concern. Rates of childhood undernutrition are particularly high in remote, rural, and upland areas. Media have the potential to play an important role in shaping health and nutrition–related behaviors and practices as well as in promoting sociocultural and economic development that might contribute to improved nutritional outcomes. This report presents the results of a media audit (MA) that was conducted to inform the development and production of mass media advocacy and communication strategies and materials with a focus on maternal and child health and nutrition that would reach the most people from the poorest communities in northern Lao PDR. Making more people aware of useful information, essential services and products and influencing them to use these effectively is the ultimate goal of mass media campaigns, and the MA measures the potential effectiveness of media efforts to reach this goal. The effectiveness of communication channels to deliver health and nutrition messages to target beneficiaries to ensure maximum reach and uptake can be viewed in terms of preferences, satisfaction, and trust. Overall, the four most accessed media channels for receiving information among communities in the study areas were village announcements, mobile phones, television, and out-of-home (OOH) media. Of the accessed media channels, the top three most preferred channels were village announcements (40 percent), television (26 percent), and mobile phones (19 percent). In terms of trust, village announcements were the most trusted source of information (64 percent), followed by mobile phones (14 percent) and television (11 percent). Hence of all the media channels, village announcements are the most preferred, have the most satisfied users, and are the most trusted source of information in study communities from four provinces in Lao PDR with some of the highest burden of childhood undernutrition.