{"type":"script","doc_desc":{"producers":[{"name":"Reproducibility WBG","abbr":"DECDI","affiliation":"World Bank - Development Impact Department","role":"Verification and preparation of metadata"}],"prod_date":"2026-03-05","version":"1"},"project_desc":{"authoring_entity":[{"name":"Nishant Yonzan","affiliation":"World Bank","email":"nyonzan@worldbank.org"},{"name":"Minh C. Nguyen","affiliation":"World Bank","email":"mnguyen3@worldbank.org"},{"name":"Christoph Lakner","affiliation":"World Bank","email":"clakner@worldbank.org"},{"name":"Aart Kraay","affiliation":"World Bank","email":"akraay@worldbank.org"},{"name":"Dean Jolliffe","affiliation":"World Bank","email":"djolliffe@worldbank.org"},{"name":"Haoyu Wu","affiliation":"World Bank","email":"hwu4@worldbank.org"},{"name":"Gabriel Lara Ibarra","affiliation":"World Bank","email":"glaraibarra@worldbank.org"}],"title_statement":{"title":"Reproducibility package for Bottom-Coding For The Measurement Of Global Poverty And Inequality","idno":"RR_WLD_2026_579"},"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. ","software":[{"name":"Stata","version":"18 MP"}],"scripts":[{"title":"Reproducibility package for Bottom-Coding For The Measurement Of Global Poverty And Inequality","date":"2026-03","notes":"Computational reproducibility verified by Development Impact (DECDI) Analytics team, World Bank.","instructions":"See README in reproducibility package.","file_name":"RR_WLD_2026_579","zip_package":"RR_WLD_2026_579.zip","dependencies":"Stata dependencies are listed in the ado folder."}],"repository_uri":[{"name":"Reproducible Research Repository (World Bank)","uri":"https:\/\/reproducibility.worldbank.org"}],"production_date":"2026-03-05","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.","geographic_units":[{"name":"World","code":"WLD"}],"keywords":[{"name":"Bottom Code"},{"name":"Consumption Floor"},{"name":"Measurement Errors"},{"name":"Distribution-Sensitive Index"},{"name":"Parametric Tail"}],"topics":[{"id":"C1","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","vocabulary":"Journal of Economic Literature (JEL)","name":"Econometric and Statistical Methods and Methodology:  General","parent_id":"C"},{"id":" D60","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","vocabulary":"Journal of Economic Literature (JEL)","name":"General","parent_id":"D6"},{"id":" I32","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","vocabulary":"Journal of Economic Literature (JEL)","name":"Measurement and Analysis of Poverty","parent_id":"I3"}],"output":[{"type":"Working Paper","description":"Policy Research Working Papers (PRWP)","title":"Bottom-Coding For The Measurement Of Global Poverty And Inequality"}],"language":[{"name":"English","code":"EN"}],"technology_requirements":"Run time: ~ 17 hours","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.","license":[{"name":"Modified BSD3","uri":"https:\/\/opensource.org\/license\/bsd-3-clause\/"}],"contacts":[{"name":"Nishant Yonzan","affiliation":"World Bank","email":"nyonzan@worldbank.org"},{"name":"Reproducibility WBG","affiliation":"World Bank","email":"reproducibility@worldbank.org"}],"technology_environment":"Paper exhibits were reproduced on a computer with the following specifications:\n\u2022 OS: Windows 11 Enterprise\n\u2022 Processor: INTEL(R) XEON(R) PLATINUM 8562Y+ 2.80 GHz (2 processors)\n\u2022 Memory available: 128 GB","reproduction_instructions":"To reproduce the findings in this paper, a replicator must:\n1. **Secure Access to Data:** Access the datasets not included in the package. See subsection Datasets for more details.\n2. **Download and Place Data:** Once the data is accessed, users should place it in the appropriate folder.\n3. **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. \n\nSince 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. ","datasets":[{"name":"World Bank Income Classification","access_type":"Data is publicly available and included in the reproducibility package.","note":"Country classification data including region, income group.\nFiles: 02-rawdata\/CLASS.dta","uri":"https:\/\/github.com\/GPID-WB\/Class\/tree\/master\/OutputData","license":"https:\/\/www.worldbank.org\/en\/about\/legal\/terms-of-use-for-datasets","license_uri":"Creative Commons Attribution 4.0 International License (CC BY 4.0)","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)","uri":"https:\/\/datacatalog.worldbank.org\/int\/data\/dataset\/0066850\/harmonized_national_poverty_lines_2017_ppp_dollars","license":"Creative Commons Attribution 4.0 (CC-BY 4.0)","license_uri":"https:\/\/datacatalog.worldbank.org\/int\/public-licenses","access_type":"Data is publicly available and included in the reproducibility package.","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","note":"Data contains country-year observations of harmonized national poverty lines, expressed in daily per capita 2017 purchasing power parity (PPP) dollars. \nFiles: 02-rawdata\/harmonized_npl.dta"},{"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). \nFiles: 02-rawdata\/P_Data_Extract_From_WDI_Database_Archives.xlsx","uri":"https:\/\/databank.worldbank.org\/source\/wdi-database-archives","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 (CC-BY 4.0)","license_uri":"https:\/\/datacatalog.worldbank.org\/public-licenses#cc-by","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.\nFiles: 02-rawdata\/P_Data_Extract_From_Food_Prices_for_Nutrition.xlsx\n","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 (CC-BY 4.0)","license_uri":"https:\/\/datacatalog.worldbank.org\/public-licenses#cc-by","uri":"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 ","citation":"World Bank, Global Monitoring Database (GMD) (version September 2024). Accessed September 2024. ","access_type":"Data access requires purchase or human approval and is not included in the reproducibility package.","note":"The dataset GMD_all_2017.dta is created from multiple household surveys contained in the World Bank\u2019s 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.","license_uri":"https:\/\/github.com\/worldbank\/datalibweb?tab=readme-ov-file#terms_use"}]},"tags":[{"tag":"DOI"},{"tag":"Limited-access Data"},{"tag":"Open Code"}],"schematype":"script"}