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Mahler, Daniel Gerszon

Development Data Group, World Bank

Fields of Specialization

Welfare economics, Inequality, Behavioral science

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Development Data Group, World Bank

Last updated: October 3, 2024

Biography

Daniel Gerszon Mahler is a Young Professional in the Development Data Group, where he is part of the Sustainable Development Statistics team. Before that, he was with the Poverty and Equity Global Practice, contributing to the practice's global agenda on measuring poverty and inequality. Daniel holds a doctorate in economics from the University of Copenhagen.

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Now showing 1 - 10 of 26

How Improved Household Surveys Influence National and International Poverty Rates
(Washington, DC: World Bank, 2024-10-03) Mahler, Daniel Gerszon; Foster, Elizabeth; Tetteh-Baah, Samuel
To effectively address poverty, it is essential that countries have the tools and means to accurately measure people’s living standards. Most countries rely on data collected from household surveys to measure monetary poverty, defining households as poor when their consumption is below the national poverty line. When countries improve the quality and scope of their household surveys, as some have done in recent years, they often capture consumption that is overlooked in previous surveys, thus leading to higher measured consumption. With better data, countries redefine their national poverty line, which on average balances out the higher consumption, leading to minimal change in national poverty rates. However, the international poverty line is fixed at any given point in time. Thus, when measured consumption increases, international poverty rates fall, sometimes dramatically. For this reason, international poverty rate comparisons over time should be done with caution when countries implement improved household surveys.
The World Bank’s New Inequality Indicator: The Number of Countries with High Inequality
(Washington, DC: World Bank, 2024-06-11) Haddad, Cameron Nadim; Mahler, Daniel Gerszon; Diaz-Bonilla, Carolina; Hill, Ruth; Lakner, Christoph; Lara Ibarra, Gabriel
The World Bank recently introduced a new key indicator to guide its work: the number of countries with high inequality, defined as a Gini index above 40. The new indicator was introduced as part of the new World Bank vision of ending poverty on a livable planet. This paper reviews why reducing inequality matters for ending poverty on a livable planet, summarizes the advantages and disadvantages of using the Gini index to track inequality, outlines challenges in measuring inequality, and discusses what a Gini threshold of 40 implies. Using the most recent data for every country, 52 countries of a total of 169 countries are classified as high inequality countries, which represents a decline from 74 countries at the beginning of the millennium.
New Evidence on Inequality of Opportunity in Sub-Saharan Africa: More Unequal Than We Thought
(Washington, DC: World Bank, 2024-03-19) Atamanov, Aziz; Cuevas, P. Facundo; Lebow, Jeremy; Mahler, Daniel Gerszon
Unequal access to economic opportunity for individuals with different innate characteristics, such as ethnicity or parents’ socioeconomic status, is often seen as both morally undesirable and bad for economic growth. This paper estimates inequality of opportunity, or the share of inequality explained by birth characteristics, across 18 countries in Sub-Saharan Africa. For many countries, this is the first time inequality of opportunity is measured. The paper uses nationally representative household survey data harmonized to allow for cross-country comparisons. Using consumption per capita as the outcome, the findings show that inequality of opportunity in Sub-Saharan Africa is stark and more pronounced than previously estimated. On average, inherited circumstances explain more than half of inequality in the region. Estimates range from 40 to 60 percent in most countries and reach 74 percent in South Africa. The findings show that birthplace, parents’ education, and ethnicity tend to be the most significant contributors, but there is large variation in the importance of circumstances across countries. This represents the most comprehensive estimate of inequality of opportunity to date in the poorest and one of the most unequal regions in the world, and it underscores the pressing need for policy makers to intensify their efforts to address inequality of opportunity to foster societies that are more equitable and unlock the full potential for growth in the region.
Missing Evidence: Tracking Academic Data Use around the World
(Washington, DC: World Bank, 2024-01-25) Stacy, Brian; Kitzmüller, Lucas; Wang, Xiaoyu; Mahler, Daniel Gerszon; Serajuddin, Umar
Data-driven research on a country is key to producing evidence-based public policies. Yet little is known about where data-driven research is lacking and how it could be expanded. This paper proposes a method for tracking academic data use by country of subject, applying natural language processing to open-access research papers. The model’s predictions produce country estimates of the number of articles using data that are highly correlated with a human-coded approach, with a correlation of 0.99. Analyzing more than 1 million academic articles, the paper finds that the number of articles on a country is strongly correlated with its gross domestic product per capita, population, and the quality of its national statistical system. The paper identifies data sources that are strongly associated with data-driven research and finds that availability of subnational data appears to be particularly important. Finally, the paper classifies countries into groups based on whether they could most benefit from increasing their supply of or demand for data. The findings show that the former applies to many low- and lower-middle-income countries, while the latter applies to many upper-middle- and high-income countries.
The Impact of COVID-19 on Global Inequality and Poverty
(World Bank, Washington, DC, 2022-10) Mahler, Daniel Gerszon; Lakner, Christoph
The COVID-19 pandemic has had catastrophic economic and human consequences worldwide. This paper tries to quantify the consequences of the pandemic on global inequality and poverty in 2020. Since face-to-face household survey data collection largely came to a halt during the pandemic, a combination of data sources is used to estimate the impacts on poverty and inequality. This includes actual household survey data, where available, high-frequency phone surveys, and country-level estimates from the literature on the impact of the pandemic on poverty and inequality. The results suggest that the world in 2020 witnessed the largest increase to global inequality and poverty since at least 1990. This paper estimates that COVID-19 increased the global Gini index by 0.7 point and global extreme poverty (using a poverty line of $2.15 per day) by 90 million people compared to counterfactual without the pandemic. These findings are primarily driven by country-level shocks to average incomes and an increase in inequality between countries. Changes to inequality within countries were mixed and relatively modest.
September 2022 Update to the Poverty and Inequality Platform (PIP): What’s New
(World Bank, Washington, DC, 2022-09) Castaneda Aguilar, R. Andres; Diaz-Bonilla, Carolina; Fujs, Tony H. M. J.; Jolliff, Dean; Lakner, Christoph; Mahler, Daniel G.; Nguyen, Minh C.; Schoch, Marta; Tetteh-Baah, Samuel K.; Viveros Mendoza, Martha C.; Wu, Haoyu; Yonzan, Nishant
The September 2022 update to the Poverty and Inequality Platform (PIP) involves two changes to the data underlying the global poverty estimates. First, this update adopts the 2017 Purchasing Power Parities (PPPs) as announced by the World Bank in May 2022. Second, this update includes five new rounds of survey data for India, making it possible to monitor poverty in the country between 2015 and 2019. This document explains these changes in detail and the reasoning behind them.
When Is There Enough Data to Create a Global Statistic ?
(Washington, DC: World Bank, 2022-05-05) Mahler, Daniel Gerszon; Maeda, Hiroko
To monitor progress toward global goals such as the Sustainable Development Goals, global statistics are needed. Yet cross-country data sets are rarely truly global, creating a trade-off for producers of global statistics: the lower is the data coverage threshold for disseminating global statistics, the more statistics can be made available, but the lower is the accuracy of these statistics. This paper quantifies the availability-accuracy trade-off by running more than 10 million simulations on the World Development Indicators. It shows that if the fraction of the world’s population for which data are lacking is x, then the global value will on expectation be off by 0.37*x standard deviation, and it could be off by as much as x standard deviations. The paper shows the robustness of this result to various assumptions and provides recommendations on when there is enough data to create global statistics. Although the decision will be context specific, in a baseline scenario, it is suggested not to create global statistics when there are data for less than half of the world’s population.
April 2022 Update to the Poverty and Inequality Platform (PIP): What's New
(World Bank, Washington, DC, 2022-04) Castaneda Aguilar, R. Andres; Dewina, Reno; Diaz-Bonilla, Carolina; Edochie, Ifeanyi N.; Fujs, Tony H. M. J.; Jolliffe, Dean; Lain, Jonathan; Lakner, Christoph; Ibarra, Gabriel Lara; Mahler, Daniel G.; Meyer, Moritz; Montes, Jose; Moreno Herrera, Laura L.; Mungai, Rose; Newhouse, David; Nguyen, Minh C.; Sanchez Castro, Diana; Schoch, Marta; Sousa, Liliana D.; Tetteh-Baah, Samuel K.; Uochi, Ikuko; Viveros Mendoza, Martha C.; Wu, Haoya; Yonzan, Nishant; Yoshida, Nobu
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.
Assessing the Impact of the 2017 PPPs on the International Poverty Line and Global Poverty
(Washington, DC: World Bank, 2022-02-21) Tetteh Baah, Samuel Kofi; Jolliffe, Dean Mitchell; Mahler, Daniel Gerszon; Lakner, Christoph; Atamanov, Aziz
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.
COVID-19 and Economic Inequality: Short-Term Impacts with Long-Term Consequences
(World Bank, Washington, DC, 2022-01) Narayan, Ambar; Cojocaru, Alexandru; Davalos, Maria; Garcia, Natalia; Lakner, Christoph; Mahler, Daniel Gerszon; Yonzan, Nishant
This paper examines the short-term implications of the COVID-19 pandemic for inequality in developing countries. The analysis takes advantage of high-frequency phone survey data collected by the World Bank to assess the distributional impacts of the pandemic through the channels of job and income losses, food insecurity, and children’s education in the early days of the pandemic and subsequent period of economic recovery leading up to early 2021. It also introduces a methodology for estimating changes in income inequality due to the pandemic by combining data from phone surveys, pre-pandemic household surveys, and macroeconomic projections of sectoral growth rates. The paper finds that the pandemic had dis-equalizing impacts both across and within countries. Even under the assumption of distribution-neutral impacts within countries, the projected income losses are estimated to be higher in the bottom half of the global income distribution. Within countries, disadvantaged groups were more likely to have experienced work and income losses initially and are recovering more slowly. Inequality simulations suggest an increase in the Gini index for 29 of 34 countries in the sample, with an average increase of about 1 percent. Although these short-term impacts on inequality appear to be small, they suggest that projections of global poverty and inequality impacts of COVID-19 under the assumption of distribution-neutral changes within countries are likely to underestimate actual impacts. Finally, the paper argues that the overall inequality impacts of COVID-19 could be larger over the medium-to-long term on account of a slow and uneven recovery in many developing countries, and disparities in learning losses during pandemic-related school closures, which will likely have long-lasting effects on inequality of opportunity and social mobility.