Publication: Poverty Traps and Nonlinear Income Dynamics with Measurement Error and Individual Heterogeneity
Loading...
Published
2005-11
ISSN
Date
2012-06-19
Author(s)
Antman, Francisca
Editor(s)
Abstract
Theories of poverty traps stand in sharp contrast to the view that anybody can make it through hard work and thrift. However, empirical detection of poverty traps is complicated by the lack of long panels, measurement error, and attrition. This paper shows how dynamic pseudo-panel methods can overcome these difficulties, allowing estimation of non-linear income dynamics and testing for the presence of poverty traps. The paper explicitly allows for individual heterogeneity in income dynamics to account for the possibility that particular groups of individuals may face traps, even if the average individual does not. These methods are used to examine the evidence for a poverty trap in labor earnings, income, and expenditure in Mexico and are compared to panel data estimates from a short rotating panel. The results do find evidence of nonlinearities in household income dynamics and demonstrate large bias in the panel data estimates. Nevertheless, even after allowing for heterogeneity and accounting for measurement error, the paper finds no evidence of the existence of a poverty trap for any group in the sample.
Link to Data Set
Citation
“Antman, Francisca; McKenzie, David J.. 2005. Poverty Traps and Nonlinear Income Dynamics with Measurement Error and Individual Heterogeneity. Policy Research Working Paper; No. 3764. © World Bank. http://hdl.handle.net/10986/8493 License: CC BY 3.0 IGO.”
Digital Object Identifier
Associated URLs
Associated content
Other publications in this report series
Publication The Economic Value of Weather Forecasts: A Quantitative Systematic Literature Review(Washington, DC: World Bank, 2025-09-10)This study systematically reviews the literature that quantifies the economic benefits of weather observations and forecasts in four weather-dependent economic sectors: agriculture, energy, transport, and disaster-risk management. The review covers 175 peer-reviewed journal articles and 15 policy reports. Findings show that the literature is concentrated in high-income countries and most studies use theoretical models, followed by observational and then experimental research designs. Forecast horizons studied, meteorological variables and services, and monetization techniques vary markedly by sector. Estimated benefits even within specific subsectors span several orders of magnitude and broad uncertainty ranges. An econometric meta-analysis suggests that theoretical studies and studies in richer countries tend to report significantly larger values. Barriers that hinder value realization are identified on both the provider and user sides, with inadequate relevance, weak dissemination, and limited ability to act recurring across sectors. Policy reports rely heavily on back-of-the-envelope or recursive benefit-transfer estimates, rather than on the methods and results of the peer-reviewed literature, revealing a science-to-policy gap. These findings suggest substantial socioeconomic potential of hydrometeorological services around the world, but also knowledge gaps that require more valuation studies focusing on low- and middle-income countries, addressing provider- and user-side barriers and employing rigorous empirical valuation methods to complement and validate theoretical models.Publication Direct and Indirect Impacts of Transport Mobility on Access to Jobs: Evidence from South Africa(Washington, DC: World Bank, 2025-11-12)Access to jobs is essential for economic growth. In Africa, unemployment rates are notably high. This paper reexamines the relationship between transport mobility and labor market outcomes, with a particular focus on the direct and indirect effects of transport connectivity. As predicted by theory, wages are influenced by the level of commuting deterrence. Generally, higher earnings are associated with longer commute times and/or higher commuting costs. Local accessibility is also important, especially for individuals with time constraints. Both direct and indirect impacts are found to be significant in South Africa, where job accessibility has been challenging since the end of apartheid. For the direct impact, the wage elasticity associated with commuting costs is significant. Returns on commute are particularly high for women. Local accessibility to socioeconomic facilities, such as shops and health services, is also found to have a significant impact, consistent with the concept of mobility of care. To enhance employment, therefore, it is crucial to connect people not only to job locations but also to various socioeconomic points of interest, such as markets and hospitals, in an integrated manner. This integration will enable individuals to spend more time working and commuting longer distances.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 From Policy to Practice: Lessons from the Implementation of the Refugee Work Rights Policy in Ethiopia(Washington, DC: World Bank, 2025-11-10)This paper examines the early implementation of Ethiopia’s refugee work rights policy, with a focus on the issuance of permits that enable refugees to engage in economic activities. Building on significant legal and institutional advances under the 2019 Refugee Proclamation and subsequent directives, the analysis explores how these reforms are being operationalized in practice. Using a mixed-methods approach, combining document review, administrative data analysis, and semi-structured interviews, the paper identifies both progress and remaining challenges. Permit issuance has increased since the adoption of detailed operational guidance in 2024, reflecting the Government of Ethiopia’s commitment to operationalizing its progressive legal framework and ensuring that refugees can exercise their right to work. However, take-up remains modest, with about 5.2 percent of the working-age population holding a permit. Preliminary evidence suggests that coordination gaps, limited subnational capacity, low awareness among refugees and employers, and disincentives to formalize in a largely informal labor market are contributing to the low take-up. The paper offers policy suggestions, grounded in the Ethiopian context and emerging evidence, to help translate legal commitments into improved labor market outcomes for refugees.Publication Monitoring Global Aid Flows: A Novel Approach Using Large Language Models(Washington, DC: World Bank, 2025-11-04)Effective monitoring of development aid is the foundation for assessing the alignment of flows with their intended development objectives. Existing reporting systems, such as the Organisation for Economic Co-operation and Development’s Creditor Reporting System, provide standardized classification of aid activities but have limitations when it comes to capturing new areas like climate change, digitalization, and other cross-cutting themes. This paper proposes a bottom-up, unsupervised machine learning framework that leverages textual descriptions of aid projects to generate highly granular activity clusters. Using the 2021 Creditor Reporting System data set of nearly 400,000 records, the model produces 841 clusters, which are then grouped into 80 subsectors. These clusters reveal 36 emerging aid areas not tracked in the current Creditor Reporting System taxonomy, allow unpacking of “multi-sectoral” and “sector not specified” classifications, and enable estimation of flows to new themes, including World Bank Global Challenge Programs, International Development Association–20 Special Themes, and Cross-Cutting Issues. Validation against both Creditor Reporting System benchmarks and International Development Association commitment data demonstrates robustness. This approach illustrates how machine learning and the new advances in large language models can enhance the monitoring of global aid flows and inform future improvements in aid classification and reporting. It offers a useful tool that can support more responsive and evidence-based decision-making, helping to better align resources with evolving development priorities.
Journal
Journal Volume
Journal Issue
Collections
Related items
Showing items related by metadata.
Publication Household Income Dynamics in Rural China(World Bank, Washington, DC, 2001-11)Theoretical work has shown that nonlinear dynamics in household incomes can yield poverty traps and distribution-dependent growth. If this is true, the potential implications for policy are dramatic: effective social protection from transient poverty would be an investment with lasting benefits, and pro-poor redistribution would promote aggregate economic growth. The authors test for nonlinearity in the dynamics of household incomes and expenditures using panel data for 6,000 households over six years in rural southwest China. While they find evidence of nonlinearity in the income and expenditure dynamics, there is no sign of a dynamic poverty trap. The authors argue that existing private and social arrangements in this setting protect vulnerable households from the risk of destitution. However, their findings imply that the speed of recovery from an income shock is appreciably slower for the poor than for others. They also find that current inequality reduces future growth in mean incomes, though the "growth cost" of inequality appears to be small. The maximum contribution of inequality is estimated to be 4-7 percent of mean income and 2 percent of mean consumption.Publication Inequality Convergence(World Bank, Washington, DC, 2001-07)Comparing changes in inequality with initial levels, using new data, the author finds that within-country inequality in income or per capita consumption is converging toward medium levels--a Gini index around 40 percent. The finding is robust to allow for serially independent measurement error in inequality data and for short-run dynamics around longer-term trends. However, the convergence process is neither rapid nor certain, and more observations over time are needed to be confident of the pattern. The author offers an approach to modeling the determinants of inequality that may be a starting point for estimating richer models.Publication Benefit Incidence with Incentive Effects, Measurement Errors and Latent Heterogeneity(World Bank, Washington, DC, 2013-08)Empirical studies of tax and benefit incidence routinely ignore behavioral responses and measurement errors. This paper offers an econometric method of estimating the mean benefit withdrawal rate (marginal tax rate) allowing for incentive effects, measurement errors, and correlated latent heterogeneity in incidence. Under the method's identifying assumptions, a feasible instrumental variables estimator corrects for incentive effects and measurement errors, and provides a bound for the true value when there is correlated incidence heterogeneity. A case study for a large cash transfer program in China indicates that past methods of assessing benefit incidence using either nominal official rates or raw tabulations from survey data are deceptive. The program entails a nominal 100 percent benefit withdrawal rate -- a poverty trap. However, the paper finds that the actual rate is much lower, and clearly too low in the light of the literature on optimal income taxation. The paper discusses likely reasons based on the qualitative observations.Publication Openness Can Be Good for Growth : The Role of Policy Complementarities(World Bank, Washington, DC, 2005-11)The authors study how the effect of trade openness on economic growth depends on complementary reforms that help a country take advantage of international competition. This issue is illustrated with a simple Harris-Todaro model where output gains after trade liberalization depend on the degree of labor market flexibility. In that model, trade protection may ameliorate the problem of underemployment (and underproduction) in sectors affected by labor market distortions. Hence, trade liberalization unambiguously increases per capita income only when labor markets are sufficiently flexible. The authors then present some panel evidence on how the growth effect of openness depends on a variety of structural characteristics. For this purpose, they use a non-linear growth regression specification that interacts a proxy of trade openness with proxies of educational investment, financial depth, inflation stabilization, public infrastructure, governance, labor-market flexibility, ease of firm entry, and ease of firm exit. They find that the growth effects of openness are positive and economically significant if certain complementary reforms are undertaken.Publication Earnings Mobility and Measurement Error : A Pseudo-Panel Approach(World Bank, Washington, DC, 2005-10)The degree of mobility in incomes is often seen as an important measure of the equality of opportunity in a society and of the flexibility and freedom of its labor market. But estimation of mobility using panel data is biased by the presence of measurement error and non-random attrition from the panel. This paper shows that dynamic pseudo-panel methods can be used to consistently estimate measures of absolute and conditional mobility in the presence of non-classical measurement errors. These methods are applied to data on earnings from a Mexican quarterly rotating panel. Absolute mobility in earnings is found to be very low in Mexico, suggesting that the high level of inequality found in the cross-section will persist over time. However, the paper finds conditional mobility to be high, so that households are able to recover quickly from earnings shocks. These findings suggest a role for policies which address underlying inequalities in earnings opportunities.
Users also downloaded
Showing related downloaded files
Publication Poverty, Prosperity, and Planet Report 2024(Washington, DC: World Bank, 2024-10-15)The Poverty, Prosperity, and Planet Report 2024 is the latest edition of the series formerly known as Poverty and Shared Prosperity. The report emphasizes that reducing poverty and increasing shared prosperity must be achieved in ways that do not come at unacceptably high costs to the environment. The current “polycrisis”—where the multiple crises of slow economic growth, increased fragility, climate risks, and heightened uncertainty have come together at the same time—makes national development strategies and international cooperation difficult. Offering the first post-Coronavirus (COVID)-19 pandemic assessment of global progress on this interlinked agenda, the report finds that global poverty reduction has resumed but at a pace slower than before the COVID-19 crisis. Nearly 700 million people worldwide live in extreme poverty with less than US$2.15 per person per day. Progress has essentially plateaued amid lower economic growth and the impacts of COVID-19 and other crises. Today, extreme poverty is concentrated mostly in Sub-Saharan Africa and fragile settings. At a higher standard more typical of upper-middle-income countries—US$6.85 per person per day—almost one-half of the world is living in poverty. The report also provides evidence that the number of countries that have high levels of income inequality has declined considerably during the past two decades, but the pace of improvements in shared prosperity has slowed, and that inequality remains high in Latin America and the Caribbean and Sub-Saharan Africa. Worldwide, people’s incomes today would need to increase fivefold on average to reach a minimum prosperity threshold of US$25 per person per day. Where there has been progress in poverty reduction and shared prosperity, there is evidence of an increasing ability of countries to manage natural hazards, but climate risks are significantly higher in the poorest settings. Nearly one in five people globally is at risk of experiencing welfare losses due to an extreme weather event from which they will struggle to recover. The interconnected issues of climate change and poverty call for a united and inclusive effort from the global community. Development cooperation stakeholders—from governments, nongovernmental organizations, and the private sector to communities and citizens acting locally in every corner of the globe—hold pivotal roles in promoting fair and sustainable transitions. By emphasizing strategies that yield multiple benefits and diligently monitoring and addressing trade-offs, we can strive toward a future that is prosperous, equitable, and resilient.Publication Business Ready 2024(Washington, DC: World Bank, 2024-10-03)Business Ready (B-READY) is a new World Bank Group corporate flagship report that evaluates the business and investment climate worldwide. It replaces and improves upon the Doing Business project. B-READY provides a comprehensive data set and description of the factors that strengthen the private sector, not only by advancing the interests of individual firms but also by elevating the interests of workers, consumers, potential new enterprises, and the natural environment. This 2024 report introduces a new analytical framework that benchmarks economies based on three pillars: Regulatory Framework, Public Services, and Operational Efficiency. The analysis centers on 10 topics essential for private sector development that correspond to various stages of the life cycle of a firm. The report also offers insights into three cross-cutting themes that are relevant for modern economies: digital adoption, environmental sustainability, and gender. B-READY draws on a robust data collection process that includes specially tailored expert questionnaires and firm-level surveys. The 2024 report, which covers 50 economies, serves as the first in a series that will expand in geographical coverage and refine its methodology over time, supporting reform advocacy, policy guidance, and further analysis and research.Publication Global Economic Prospects, June 2025(Washington, DC: World Bank, 2025-06-10)The global economy is facing another substantial headwind, emanating largely from an increase in trade tensions and heightened global policy uncertainty. For emerging market and developing economies (EMDEs), the ability to boost job creation and reduce extreme poverty has declined. Key downside risks include a further escalation of trade barriers and continued policy uncertainty. These challenges are exacerbated by subdued foreign direct investment into EMDEs. Global cooperation is needed to restore a more stable international trade environment and scale up support for vulnerable countries grappling with conflict, debt burdens, and climate change. Domestic policy action is also critical to contain inflation risks and strengthen fiscal resilience. To accelerate job creation and long-term growth, structural reforms must focus on raising institutional quality, attracting private investment, and strengthening human capital and labor markets. Countries in fragile and conflict situations face daunting development challenges that will require tailored domestic policy reforms and well-coordinated multilateral support.Publication Commodity Markets Outlook, April 2025(Washington, DC: World Bank, 2025-04-29)Commodity prices are set to fall sharply this year, by about 12 percent overall, as weakening global economic growth weighs on demand. In 2026, commodity prices are projected to reach a six-year low. Oil prices are expected to exert substantial downward pressure on the aggregate commodity index in 2025, as a marked slowdown in global oil consumption coincides with expanding supply. The anticipated commodity price softening is broad-based, however, with more than half of the commodities in the forecast set to decrease this year, many by more than 10 percent. The latest shocks to hit commodity markets extend a so far tumultuous decade, marked by the highest level of commodity price volatility in at least half a century. Between 2020 and 2024, commodity price swings were frequent and sharp, with knock-on consequences for economic activity and inflation. In the next two years, commodity prices are expected to put downward pressure on global inflation. Risks to the commodity price projections are tilted to the downside. A sharper-than-expected slowdown in global growth—driven by worsening trade relations or a prolonged tightening of financial conditions—could further depress commodity demand, especially for industrial products. In addition, if OPEC+ fully unwinds its voluntary supply cuts, oil production will far exceed projected consumption. There are also important upside risks to commodity prices—for instance, if geopolitical tensions worsen, threatening oil and gas supplies, or if extreme weather events lead to agricultural and energy price spikes.Publication Global Economic Prospects, January 2025(Washington, DC: World Bank, 2025-01-16)Global growth is expected to hold steady at 2.7 percent in 2025-26. However, the global economy appears to be settling at a low growth rate that will be insufficient to foster sustained economic development—with the possibility of further headwinds from heightened policy uncertainty and adverse trade policy shifts, geopolitical tensions, persistent inflation, and climate-related natural disasters. Against this backdrop, emerging market and developing economies are set to enter the second quarter of the twenty-first century with per capita incomes on a trajectory that implies substantially slower catch-up toward advanced-economy living standards than they previously experienced. Without course corrections, most low-income countries are unlikely to graduate to middle-income status by the middle of the century. Policy action at both global and national levels is needed to foster a more favorable external environment, enhance macroeconomic stability, reduce structural constraints, address the effects of climate change, and thus accelerate long-term growth and development.