[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-113310-en":3,"doc-seo-113310-105":29,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":13,"seo_description":14,"update_tm":27,"read_time":28},113310,1099514068035,"Ezra","https://ap-avatar.wpscdn.com/davatar_276721f389ce27ea32af1340a28f341c",8,"Research & Report","Consumption Subaggregates Should Not Be Used to Measure Poverty","Frequent poverty measurement is difficult because it often depends on complex, expensive expenditure surveys that compile a comprehensive consumption aggregate. This paper evaluates whether cheaper “consumption subaggregates” can replace full aggregates. The approach is only theoretically valid under very stringent conditions: all Engel curves must be linear for any price realization. Using data from Rwanda, Tanzania, and Uganda, the study constructs linear subaggregates but finds them unreliable in practice and questions cross-country poverty tracking consistency.","Pub lic Disclosure Authorized Pub lic Disclosure Authorized  \nThe World Bank Economic Review, 36(2), 2022, 413–432  \n[https://doi.org10.1093/wber/lhab021](https://doi.org10.1093/wber/lhab021)  \nArticle  \nConsumption Subaggregates Should Not Be Used to Measure Poverty  \nLuc Christiaensen, Ethan Ligon , and Thomas Pave Sohnesen Abstract  \nFrequent measurement of poverty is challenging because measurement often relies on complex and expensive expenditure surveys that try to measure expenditures on a comprehensive consumption aggregate. This paper investigates the use of consumption “subaggregates” instead. The use of consumption subaggregates is theoretically justified if and only if all Engel curves are linear for any realization of prices. This is very stringent. However, it may be possible to empirically identify certain goods that happen to have linear Engel curves given prevailing prices, and when the effect of price changes is small, such a subaggregate might work in practice. The paper constructs such linear subaggregates using data from Rwanda, Tanzania, and Uganda. The findings show that using subaggregates is ill advised in practice as well as in theory. This also raises questions about the consistency of the poverty tracking efforts currently applied across countries, since obtaining exhaustive consumption measures remains an unmet challenge.  \nJEL classification: D11, D12, I32  \nKeywords: consumption subaggregates, poverty, Engel curves  \n1. Introduction  \nDirectly and comprehensively recording nondurable consumption expenditures via large-scale (face-toface) household surveys is generally regarded as the best way to assess the prevalence of poverty in lowincome countries. Comprehensive checklists prompt respondents to remember their consumption more completely and accurately. But administering lengthy in-person questionnaires is costly, and long questionnaires are often not compatible with other, cheaper survey formats, such as phone surveys, or simply not feasible, as in fragile and conflict-ridden contexts (Pape and Mistiaen 2018) . As a result, comprehensive consumption expenditure surveys (or survey modules) are conducted in fewer places, with smaller samples, and with lower frequency than is desirable if our aim is to accurately track changes in poverty over time (Beegle et al. 2016) .  \nThis study considers one possible approach to reducing the cost of measuring poverty, using what we call consumption “subaggregates.” Rather than collecting data on a comprehensive set of consumption expenditures and summing these, perhaps one could collect data on an inexpensively measured subset and consider only the sum of these. The theory behind this approach builds on an idea found in  \nLuc Christiaensen is a Lead Agriculture Economist in the Jobs Group of the World Bank; his email address is[lchristiaensen@worldbank.org. Ethan Ligon](lchristiaensen@worldbank.org. Ethan Ligon) (corresponding author) is Professor of Agricultural & Resource Economics atthe University of California, Berkeley; his email address is [ligon@berkeley.edu. Thomas](ligon@berkeley.edu. Thomas) Pave Sohnesen is an Independent Consultant, Copenhagen, Denmark; his email address is [sohnesen@gmail.com](sohnesen@gmail.com).  \n© The Author(s) 2021 . Published by Oxford University Press on behalf of the International Bank for Reconstruction and Development / THE WORLD BANK.  \nAll rights reserved. For permissions, please e-mail: [journals.permissions@oup.com](journals.permissions@oup.com)  \nDownloaded from [https://academic.oup.com/wber/article/36/2/413/6364497 by LEGVP Law Library user on 08 December 2023](https://academic.oup.com/wber/article/36/2/413/6364497 by LEGVP Law Library user on 08 December 2023)  \nLanjouw and Lanjouw (2001), who imagine constructing poverty measures by observing only food expenditures (a particular possible subaggregate), and establish conditions under which the Foster–Greer– Thorbecke (FGT) family of poverty measures will yield ","cbCaicRy3lU2jDAr","https://ap.wps.com/l/cbCaicRy3lU2jDAr","pdf",686395,1,20,"English","en",105,"# Introduction\n## Related Approaches","[{\"question\":\"Why is measuring poverty difficult in practice?\",\"answer\":\"Poverty measurement often relies on costly, complex expenditure surveys to capture a comprehensive consumption aggregate, which limits coverage and frequency.\"},{\"question\":\"When is the use of consumption subaggregates theoretically justified?\",\"answer\":\"Only if all Engel curves are linear for any realization of prices, which is a very stringent condition.\"},{\"question\":\"What do the empirical results from Rwanda, Tanzania, and Uganda show?\",\"answer\":\"Constructed linear subaggregates cannot reliably replicate poverty measures, and using subaggregates is ill advised in both theory and 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