[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-112840-en":3,"doc-seo-112840-105":29,"detail-sidebar-cat-0-en-105":90},{"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":4,"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},112840,962075114101,"Seraphina","https://ap-avatar.wpscdn.com/avatar/e000253a75eb197efd?x-image-process=image/resize,m_fixed,w_180,h_180&k=1780044092746381165",8,"Research & Report","The ABCDE of Big Data - Assessing Biases in Call-Detail Records for Development Estimates","This article improves understanding of biases in development-related demographic indicator estimates using Call Detail Records (CDRs), an important but non-representative data source in developing contexts. Using Senegal data from 2013, it combines CDRs with census records to evaluate biases in population density estimates. Results show systematic links between phone use and socio-economic or geographic factors, a difference-in-differences strategy to reduce bias without ground-truth, and the monitoring of development indicators by integrating census and CDR information over time and space.","Pub lic Disclosure Authorized Pub lic Disclosure Authorized  \nThe World Bank Economic Review, 34(Supplement), 2020, S89–S97 doi: 10.1093/wber/lhz039 Supplementary Article  \nThe ABCDE of Big Data: Assessing Biases in Call-Detail Records for Development Estimates Gabriel Pestre, Emmanuel Letouzé, and Emilio Zagheni  \nAbstract  \nThis article contributes to improving our understanding of biases in estimates of demographic indicators, in the developing world, based on Call Detail Records (CDRs) . CDRs represent an important and largely untapped source of data for the developing world. However, they are not representative of the underlying population. We combine CDRs and census data for Senegal in 2013 to evaluate biases related to estimates of population density. We show that: (i) there are systematic relationships between cell-phone use and socio-economic and geographic characteristics that can be leveraged to improve estimates of population density; (ii) when no ‘ground truth’data is available, a difference-in-difference approach can be used to reduce bias and infer relative changes overtime in population size at the subnational level; (iii) indicators of development, including urbanization and internal, circular, and temporary migration, can be monitored by integrating census data and CDRs. The paper is intended to offer a methodological contribution and examples of applications related to combining new and traditional data sources to improve our ability to monitor development indicators over time and space.  \nJEL classification: C82  \nKeywords: Big Data, national statistics, demographic indicators, call detail records, sample bias correction, digital breadcrumbs  \n1. Context and Objective  \nThis paper aims to shed light on a critical, yet under-researched, challenge for using Big Data to produce development estimates: the challenge is that most of these data have not been collected for inference purposes, such that the sample of people who self-select into using certain devices, services, and/or providers, and are typically not representative of their underlying population, especially in developing countries. This study uses cell-phone call detail records (CDRs) made available as part of the 2014 Orange Data  \nGabriel Pestre is an MS candidate in Data Science at Harvard University; his email address is [gpestre@gmail.com. Em](gpestre@gmail.com. Em)manuel Letouzé is the director and co-founder of Data-Pop Alliance; his email address is [eletouze@datapopalliance.org](eletouze@datapopalliance.org). Emilio Zagheni (corresponding author) is director of the Max Planck Institute for Demographic Research; his email address is zagheni@demogr.mpg.de. This paper benefited from the financial support of the World Bank Group, which is gratefully acknowledged. The Call Detail Records (CDRs) were made available by Orange/Sonatel within the framework of the Data for Development (D4D) Challenge. Permission was obtained for their use in the context of Data-Pop Alliance’s work on sample selection bias correction, and authors are grateful to Orange/Sonatel for facilitating access to these CDRs. The Census datasets from Senegal’s 2013 Recensement Général de la Population et de l’Habitat, de l’Agriculture et de l’Elevage (RGPHAE) were provided by the Agence Nationale de la Statistique et de la Démographie (ANSD) . The authors wish to thank the ANSD for its help in accessing and using the Census data.  \n© The Author(s) 2019 . 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/34/Supplement_1/S89/5650800 by guest on 23 June 2021](https://academic.oup.com/wber/article/34/Supplement_1/S89/5650800 by guest on 23 June 2021)  \nfor Development (D4D) Senegal Challenge to estimate population size down to the third ad","cbCaiu4BFOe5TvCx","https://ap.wps.com/l/cbCaiu4BFOe5TvCx","pdf",1168822,1,9,"English","en",105,"# Abstract\n# Context and Objective\n## Data challenge: non-representative self-selection\n## Study design for Senegal (2013)","[{\"question\":\"Why are call-detail records (CDRs) prone to bias in development estimates?\",\"answer\":\"Because CDRs are not collected for inference and reflect the subset of people who self-select into using specific devices, services, and providers, which may not represent the underlying population.\"},{\"question\":\"How does the study reduce bias when no ground-truth data is available?\",\"answer\":\"It uses a difference-in-differences approach to reduce bias and infer relative changes over time in population size at the subnational level.\"},{\"question\":\"What data sources does the study combine for Senegal, and what indicators can be monitored?\",\"answer\":\"It combines CDRs with Senegal 2013 census data (RGPHAE) to evaluate biases and monitor development indicators including urbanization and circular/temporary internal migration.\"}]",1784497568,23,{"code":4,"msg":30,"data":31},"ok",{"site_id":24,"language":23,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":85,"head_meta":87,"extra_data":89,"updated_unix":27},"the-abcde-of-big-data-assessing-biases-in-call-detail-records-for-development-estimates","",{"@graph":35,"@context":84},[36,53,67],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,50],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":42,"position":52},"https://docshare.wps.com/document/the-abcde-of-big-data-assessing-biases-in-call-detail-records-for-development-estimates/112840/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":23,"description":14,"dateModified":61,"datePublished":61,"encodingFormat":60,"isAccessibleForFree":62,"interactionStatistic":63},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":40,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-19",true,{"@type":64,"interactionType":65,"userInteractionCount":4},"InteractionCounter",{"@type":66},"ViewAction",{"@type":68,"mainEntity":69},"FAQPage",[70,76,80],{"name":71,"@type":72,"acceptedAnswer":73},"Why are call-detail records (CDRs) prone to bias in development estimates?","Question",{"text":74,"@type":75},"Because CDRs are not collected for inference and reflect the subset of people who self-select into using specific devices, services, and providers, which may not represent the underlying population.","Answer",{"name":77,"@type":72,"acceptedAnswer":78},"How does the study reduce bias when no ground-truth data is available?",{"text":79,"@type":75},"It uses a difference-in-differences approach to reduce bias and infer relative changes over time in population size at the subnational level.",{"name":81,"@type":72,"acceptedAnswer":82},"What data sources does the study combine for Senegal, and what indicators can be monitored?",{"text":83,"@type":75},"It combines CDRs with Senegal 2013 census data (RGPHAE) to evaluate biases and monitor development indicators including urbanization and circular/temporary internal migration.","https://schema.org",{"og:url":51,"og:type":86,"og:title":13,"og:site_name":58,"og:description":14},"article",{"robots":88,"canonical":51},"index,follow",{"doc_id":7,"site_id":24},{"code":4,"msg":5,"data":91},[92,96,100,104,109,114,119,122,126,129,133],{"id":20,"doc_module":4,"doc_module_name":45,"category_name":93,"show_sort_weight":94,"slug":95},"Story & Novel",90,"story-novel",{"id":46,"doc_module":4,"doc_module_name":45,"category_name":97,"show_sort_weight":98,"slug":99},"Literature",80,"literature",{"id":52,"doc_module":4,"doc_module_name":45,"category_name":101,"show_sort_weight":102,"slug":103},"Exam",70,"exam",{"id":105,"doc_module":4,"doc_module_name":45,"category_name":106,"show_sort_weight":107,"slug":108},5,"Comic",60,"comic",{"id":110,"doc_module":4,"doc_module_name":45,"category_name":111,"show_sort_weight":112,"slug":113},6,"Technology",50,"technology",{"id":115,"doc_module":4,"doc_module_name":45,"category_name":116,"show_sort_weight":117,"slug":118},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":45,"category_name":12,"show_sort_weight":120,"slug":121},30,"research-report",{"id":21,"doc_module":4,"doc_module_name":45,"category_name":123,"show_sort_weight":124,"slug":125},"Religion & Spirituality",20,"religion-spirituality",{"id":124,"doc_module":4,"doc_module_name":45,"category_name":127,"show_sort_weight":124,"slug":128},"World Cup","world-cup",{"id":130,"doc_module":4,"doc_module_name":45,"category_name":131,"show_sort_weight":130,"slug":132},10,"Lifestyle","lifestyle",{"id":134,"doc_module":4,"doc_module_name":45,"category_name":135,"show_sort_weight":105,"slug":136},19,"General","general"]