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PRWP

Reproducibility package for Bottom-Coding For The Measurement Of Global Poverty And Inequality

2026
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Reference ID
RR_WLD_2026_579
Author(s)
Nishant Yonzan, Minh C. Nguyen, Christoph Lakner, Aart Kraay, Dean Jolliffe, Haoyu Wu, Gabriel Lara Ibarra
Collections
World Bank Policy Research Working Papers
Metadata
JSON
Created on
Mar 06, 2026
Last modified
Mar 13, 2026
  • Overview
  • Reproducibility Package
  • Description
  • Scope and coverage
  • Disclaimer
  • Access and rights
  • Contacts
  • Information on metadata

    • Overview

    Abstract

    Distribution sensitive welfare and poverty measures are designed to respond to low values of individual income or consumption. However, very small positive values can have an extreme influence on many distribution sensitive measures, and some measures are not defined for nonpositive values. While income or consumption often are truncated or bottom-coded at some strictly positive threshold to avoid these difficulties, it is unclear where the threshold should be drawn, and data providers follow different practices. This paper systematically explores various options for bottom-coding consumption and income distributions when calculating summary welfare and poverty measures for cross-country and over-time comparisons. Using over 800 consumption surveys from across the world and employing various methodologies, this paper suggests that $0.25 per person per day in 2017 purchasing power parity is a suitable bottom-coding threshold in this setting.

    Reproducibility Package

    Scripts
    Get Reproducibility Package
    File name
    RR_WLD_2026_579
    Zip package
    RR_WLD_2026_579.zip
    Title
    Reproducibility package for Bottom-Coding For The Measurement Of Global Poverty And Inequality
    Date
    2026-03
    Dependencies
    Stata dependencies are listed in the ado folder.
    Instructions
    See README in reproducibility package.
    Notes
    Computational reproducibility verified by Development Impact (DECDI) Analytics team, World Bank.
    Source code repository
    Repository name URI
    Reproducible Research Repository (World Bank) https://reproducibility.worldbank.org
    Software
    Name
    Stata
    Version
    18 MP

    Reproducibility

    Technology environment

    Paper exhibits were reproduced on a computer with the following specifications:
    • OS: Windows 11 Enterprise
    • Processor: INTEL(R) XEON(R) PLATINUM 8562Y+ 2.80 GHz (2 processors)
    • Memory available: 128 GB
    Technology requirements

    Run time: ~ 17 hours
    Reproduction instructions

    To reproduce the findings in this paper, a replicator must:

    1. Secure Access to Data: Access the datasets not included in the package. See subsection Datasets for more details.
    2. Download and Place Data: Once the data is accessed, users should place it in the appropriate folder.
    3. Run the Package: After placing the data in the folder, update the global in line 12 of the do-file "00_Master", and run the do-file.

    Since all the data is not included, the package includes the results produced by replicators. These files can be used to review the results presented in the paper.

    Data

    Datasets
    Name
    World Bank Income Classification
    Note
    Country classification data including region, income group. Files: 02-rawdata/CLASS.dta
    Access policy
    Data is publicly available and included in the reproducibility package.
    License
    https://www.worldbank.org/en/about/legal/terms-of-use-for-datasets
    License URL
    Creative Commons Attribution 4.0 International License (CC BY 4.0)
    Data URL
    https://github.com/GPID-WB/Class/tree/master/OutputData
    Citation
    World Bank. 2025. "World Bank Income Classification" [dataset]. https://github.com/GPID-WB/Class/tree/master/OutputData. Accessed January 15, 2025
    Name
    Harmonized national poverty lines (2017 PPP dollars)
    Note
    Data contains country-year observations of harmonized national poverty lines, expressed in daily per capita 2017 purchasing power parity (PPP) dollars. Files: 02-rawdata/harmonized_npl.dta
    Access policy
    Data is publicly available and included in the reproducibility package.
    License
    Creative Commons Attribution 4.0 (CC-BY 4.0)
    License URL
    https://datacatalog.worldbank.org/int/public-licenses
    Data URL
    https://datacatalog.worldbank.org/int/data/dataset/0066850/harmonized_national_poverty_lines_2017_ppp_dollars
    Citation
    Jolliffe, D., Mahler, D.G., Lakner, C., Atamanov, A., Tetteh-Baah, S.K., 2024. Poverty and Prices: Assessing the Impact of the 2017 PPPs on the International Poverty Line and Global Poverty. The World Bank Economic Review lhae035. https://doi.org/10.1093/wber/lhae035
    Name
    World Development Indicators
    Note
    Indicator accessed: GDP per capita, PPP (constant 2011 international $) for 2017 from World Development Indicators database archives (March 2024 vintage). Files: 02-rawdata/P_Data_Extract_From_WDI_Database_Archives.xlsx
    Access policy
    Data is publicly available and included in the reproducibility package.
    License
    Creative Commons Attribution 4.0 (CC-BY 4.0)
    License URL
    https://datacatalog.worldbank.org/public-licenses#cc-by
    Data URL
    https://databank.worldbank.org/source/wdi-database-archives
    Citation
    World Bank. 2024. "World Development Indicators" [dataset]. Indicator accessed: GDP per capita, PPP (constant 2011 international $). Accessed in February 2026. https://databank.worldbank.org/source/wdi-database-archives
    Name
    Food Prices for Nutrition
    Note
    Indicator accessed: Cost of energy sufficient diet in PPP dollars for the year 2017 from classification Food Prices for Nutrition 4.0. Files: 02-rawdata/P_Data_Extract_From_Food_Prices_for_Nutrition.xlsx
    Access policy
    Data is publicly available and included in the reproducibility package.
    License
    Creative Commons Attribution 4.0 (CC-BY 4.0)
    License URL
    https://datacatalog.worldbank.org/public-licenses#cc-by
    Data URL
    https://databank.worldbank.org/source/food-prices-for-nutrition#
    Citation
    World Bank. 2024. "Food Prices for Nutrition " [dataset]. Indicator accessed: Cost of energy sufficient diet in PPP dollars. Accessed in February 2024. https://databank.worldbank.org/source/food-prices-for-nutrition#
    Name
    Global Monitoring Database 2017
    Note
    The dataset GMD_all_2017.dta is created from multiple household surveys contained in the World Bank’s Global Monitoring Database (GMD). Most of these surveys can be accessed by World Bank staff through the datalibweb Stata package. The file Supplementary files/BottomCoding-SurveyList.xlsx lists all surveys used in the paper, and the do-file Supplementary files/01-PrepData.do documents the steps required to construct GMD_all_2017.dta once access to the underlying surveys is granted. Because many surveys require permission or approval, users may need to request access through Datalibweb (https://datalibweb2.worldbank.org/about) or contact the authors to obtain the dataset.
    Access policy
    Data access requires purchase or human approval and is not included in the reproducibility package.
    License URL
    https://github.com/worldbank/datalibweb?tab=readme-ov-file#terms_use
    Citation
    World Bank, Global Monitoring Database (GMD) (version September 2024). Accessed September 2024.
    Data statement

    Some data is limited-access and has not been included in the reproducibility package. For more details, please refer to the README file.

    Description

    Output
    Type
    Working Paper
    Title
    Bottom-Coding For The Measurement Of Global Poverty And Inequality
    Description
    Policy Research Working Papers (PRWP)
    Authors
    Author Affiliation Email
    Nishant Yonzan World Bank nyonzan@worldbank.org
    Minh C. Nguyen World Bank mnguyen3@worldbank.org
    Christoph Lakner World Bank clakner@worldbank.org
    Aart Kraay World Bank akraay@worldbank.org
    Dean Jolliffe World Bank djolliffe@worldbank.org
    Haoyu Wu World Bank hwu4@worldbank.org
    Gabriel Lara Ibarra World Bank glaraibarra@worldbank.org
    Date of production

    2026-03-05

    Scope and coverage

    Geographic locations
    Location Code
    World WLD
    Keywords
    Bottom Code Consumption Floor Measurement Errors Distribution-Sensitive Index Parametric Tail
    Topics
    ID Topic Parent topic ID Vocabulary Vocabulary URI
    C1 Econometric and Statistical Methods and Methodology: General C Journal of Economic Literature (JEL)
    D60 General D6 Journal of Economic Literature (JEL)
    I32 Measurement and Analysis of Poverty I3 Journal of Economic Literature (JEL)

    Disclaimer

    Disclaimer

    The materials in the reproducibility packages are distributed as they were prepared by the staff of the International Bank for Reconstruction and Development/The World Bank. The findings, interpretations, and conclusions expressed in this event do not necessarily reflect the views of the World Bank, the Executive Directors of the World Bank, or the governments they represent. The World Bank does not guarantee the accuracy of the materials included in the reproducibility package.

    Access and rights

    License
    Name URI
    Modified BSD3 https://opensource.org/license/bsd-3-clause/

    Contacts

    Contacts
    Name Affiliation Email
    Nishant Yonzan World Bank nyonzan@worldbank.org
    Reproducibility WBG World Bank reproducibility@worldbank.org

    Information on metadata

    Producers
    Name Abbreviation Affiliation Role
    Reproducibility WBG DECDI World Bank - Development Impact Department Verification and preparation of metadata
    Date of Production

    2026-03-05
    Document version

    1
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