{"type":"script","doc_desc":{"producers":[{"name":"Reproducibility WBG","abbr":"DECDI","affiliation":"World Bank - Development Impact Department","role":"Verification and preparation of metadata"}],"prod_date":"2026-09-08","version":"1"},"project_desc":{"authoring_entity":[{"name":"David McKenzie","affiliation":"World Bank","email":"dmckenzie@worldbank.org"},{"name":"Jacobus Cilliers","affiliation":"Georgetown University","email":"ejc93@georgetown.edu"},{"name":"Nour Elashmawy","affiliation":"World Bank","email":"nelashmawy@worldbank.org"}],"title_statement":{"title":"Reproducibility package for Using Post-Double Selection Lasso In Field Experiments","idno":"PP_WLD_2026_544"},"data_statement":"All data sources are publicly available and included in the reproducibility package.","software":[{"name":"Stata","version":"18.5 MP"}],"scripts":[{"title":"Reproducibility package for Using Post-Double Selection Lasso In Field Experiments","date":"2026-09","notes":"Computational reproducibility verified by Development Impact (DECDI) Analytics team, World Bank.","instructions":"See README in reproducibility package.","file_name":"PP_WLD_2026_544","zip_package":"PP_WLD_2026_544.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":"2026-09-08","abstract":"The post-double selection Lasso estimator has become a popular way of selecting control variables when analyzing randomized experiments. This is done to try to reduce specification searching, improve precision, and reduce bias from attrition or chance imbalances. We re-estimate 743 treatment effects from published papers to examine how much difference this approach makes in practice. We find it reduces standard errors by less than one percent compared to standard Ancova on average and does not select variables to model treatment in over half the cases.  The case for using this method instead of OLS or Ancova is limited.","geographic_units":[{"name":"World","code":"WLD"}],"keywords":[{"name":"Field Experiments"},{"name":"Selecting Control Variables"},{"name":"Post-Double Lasso"},{"name":"Machine Learning"}],"topics":[{"id":"C93","vocabulary":"JEL Classifications","name":" Field Experiments ","url":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel"},{"id":"C21","vocabulary":"JEL Classifications","name":" Single Equation Models; Single Variables: Cross-Sectional Models; Spatial Models; Treatment Effect Models; Quantile Regressions ","url":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel"},{"id":"O12","vocabulary":"JEL Classifications","name":" Microeconomic Analyses of Economic Development ","url":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel"}],"output":[{"type":"Journal Article","description":"Journal Articles","title":"Using Post-Double Selection Lasso In Field Experiments"}],"language":[{"name":"English","code":"EN"}],"technology_requirements":"Run time: ~ 2 days","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":"MIT License","uri":"https:\/\/opensource.org\/license\/mit"},{"name":"World Bank IGO Rider","uri":"https:\/\/github.com\/worldbank\/metadata-editor\/blob\/main\/WB-IGO-RIDER.md"}],"contacts":[{"name":"David McKenzie","affiliation":"World Bank","email":"dmckenzie@worldbank.org"},{"name":"Reproducibility WBG","affiliation":"World Bank","email":"reproducibility@worldbank.org"}],"datasets":[{"name":"Replication Data for: The Value of Reference Letters (Abel, Burger, and Piraino 2020)","note":"File location: external_data_code\/AEJApplied\/Abel et al 2020\/. Original replication data and code for the underlying AEJ:Applied field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/www.openicpsr.org\/openicpsr\/project\/231482\/version\/V1\/view?path=\/openicpsr\/231482\/fcr:versions\/V1\/LICENSE.txt&type=file#","uri":"https:\/\/www.aeaweb.org\/journals\/dataset?id=10.1257\/app.20180666","citation":"Abel, Martin, Rulof Burger, and Patrizio Piraino. 2020. \"Replication package for: The Value of Reference Letters: Experimental Evidence from South Africa.\" [dataset]. American Economic Association. https:\/\/www.aeaweb.org\/journals\/dataset?id=10.1257\/app.20180666."},{"name":"Replication Data for: Does Diversity Matter for Health? (Alsan, Garrick, and Graziani 2019)","note":"File location: external_data_code\/AER\/Alsanetal2019\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/www.openicpsr.org\/openicpsr\/project\/231420\/version\/V1\/view?path=\/openicpsr\/231420\/fcr:versions\/V1\/LICENSE.txt&type=file#","uri":"https:\/\/doi.org\/10.3886\/E231420V1","citation":"Alsan, Marcella, Owen Garrick, and Grant Graziani. 2019. \"Replication data for: Does Diversity Matter for Health? Experimental Evidence from Oakland.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E231420V1."},{"name":"Data and Code for: Upping the Ante (Andrabi et al. 2020)","note":"File location: external_data_code\/AER\/Andrabietal2020\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E118805V1","citation":"Andrabi, Tahir, Jishnu Das, Asim Khwaja, Selcuk Ozyurt, and Niharika Singh. 2020. \"Data and Code for: Upping the Ante: The Equilibrium Effects of Unconditional Grants to Private Schools.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E118805V1."},{"name":"Data and Code for: Does Information Break the Political Resource Curse? (Armand et al. 2020)","note":"File location: external_data_code\/AER\/Armandetal2020\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E119785V1","citation":"Armand, Alex, Alexander Coutts, Pedro C. Vicente, and In\u00eas Vilela. 2020. \"Data and Code for: Does Information Break the Political Resource Curse? Experimental Evidence from Mozambique.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E119785V1."},{"name":"Data for: When Nature Calls Back (Augsburg et al. 2022)","note":"File location: external_data_code\/JDE\/Augsburg et al\/. Original replication data and code for the underlying JDE field experiment, redistributed as part of this deposit via Mendeley Data; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.17632\/95vgh7k4yk.1","citation":"Augsburg, Britta, Antonella Bancalari, Zara Durrani, Madhav Vaidyanathan, and Zach White. 2022. \"When nature calls back: Sustaining behavioral change in rural Pakistan.\" [dataset]. Mendeley Data, V1. https:\/\/doi.org\/10.17632\/95vgh7k4yk.1."},{"name":"Data and Code for: Teaching Labor Laws (Bertrand and Cr\u00e9pon 2021)","note":"File location: external_data_code\/AEJApplied\/Bertrand et al 2021\/. Original replication data and code for the underlying AEJ:Applied field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E120311V1","citation":"Bertrand, Marianne, and Bruno Cr\u00e9pon. 2021. \"Data and Code for: Teaching Labor Laws: Evidence From A Randomized Control Trial in South Africa.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E120311V1."},{"name":"Data and Code for: The Impacts of a Multifaceted Pre-natal Intervention (Carneiro et al. 2021, deposited under Rasul et al. 2021)","note":"File location: external_data_code\/AER\/Carneiroetal2021\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; the openICPSR deposit is registered under the Rasul et al. (2021) citation. Re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E131421V1","citation":"Rasul, Imran. 2021. \"Data and Code for: The Impacts of a Multifaceted Pre-natal Intervention on Human Capital Accumulation in Early Life.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E131421V1."},{"name":"Data and Code for: Reshaping Adolescents' Gender Attitudes (Dhar, Jain, and Jayachandran 2022)","note":"File location: external_data_code\/AER\/Dharetal2022\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E149882V1","citation":"Dhar, Diva, Tarun Jain, and Seema Jayachandran. 2022. \"Data and Code for: Reshaping Adolescents' Gender Attitudes: Evidence from a School-Based Experiment in India.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E149882V1."},{"name":"Replication Data for: Seeking the Treated (Fernando 2021)","note":"File location: external_data_code\/JDE\/Fernando\/. Original replication data and code for the underlying JDE field experiment; redistributed in this deposit with written email permission from the author (archived in permissions\/Fernando_permission.pdf), rather than via a public repository. Author's original distribution point: Dropbox link https:\/\/www.dropbox.com\/scl\/fi\/n57mxai01f8qgg6ppfld7\/replication_package.zip?rlkey=m1ucxl9l0c2nq6pyddol2dtkw&e=1&dl=0. Re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data access was granted directly to the study authors by the data owners\/managers. It was obtained with a custom data license and it is included in the reproducibility package.","license":"Custom","citation":"Fernando, A. Nilesh. 2021. \"Replication data for: Seeking the treated: The impact of mobile extension on farmer information exchange in India.\" Journal of Development Economics 153: 102713."},{"name":"Data and Code for: All Eyes on Them (Garbiras-D\u00edaz and Montenegro 2022)","note":"File location: external_data_code\/AER\/Garbiras-D\u00edazandMontenegro2022\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E160921V2","citation":"Garbiras-D\u00edaz, Natalia, and Mateo Montenegro. 2024 [2022 publication]. \"Data and Code for: All Eyes on Them: A Field Experiment on Citizen Oversight and Electoral Integrity.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E160921V2."},{"name":"Supplementary Data for: Environmental Effects of Development Programs (He\u00df, Jaimovich, and Sch\u00fcndeln 2021)","note":"File location: external_data_code\/JDE\/He\u00df et al\/. Original replication data and code for the underlying JDE field experiment, redistributed under Elsevier's journal supplementary-material policy (publicly downloadable from ScienceDirect); re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Elsevier journal supplementary-material terms","license_uri":"https:\/\/www.elsevier.com\/legal\/elsevier-website-terms-and-conditions","uri":"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0304387821001085#appSB","citation":"He\u00df, Simon, Dany Jaimovich, and Matthias Sch\u00fcndeln. 2021. \"Environmental effects of development programs: Experimental evidence from West African dryland forests.\" Journal of Development Economics 153: 102737. Supplementary data (Appendix A): https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0304387821001085#appSB."},{"name":"Data and Code for: Rational Habit Formation (Hussam et al. 2022)","note":"File location: external_data_code\/AER\/Hussametal2022a\/. Original replication data and code for the underlying AER field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E117401V1","citation":"Hussam, Reshmaan, Natalia Rigol, Giovanni Reggiani, and Atonu Rabbani. 2022. \"Data and Code for: Rational Habit Formation: Experimental Evidence From Handwashing In India.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E117401V1."},{"name":"Supplementary Data for: The Effects of Chess Instruction (Islam, Lee, and Nicholas 2021)","note":"File location: external_data_code\/JDE\/Islam et al\/. Original replication data and code for the underlying JDE field experiment, redistributed under Elsevier's journal supplementary-material policy (publicly downloadable from ScienceDirect); re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Elsevier journal supplementary-material terms","license_uri":"https:\/\/www.elsevier.com\/legal\/elsevier-website-terms-and-conditions","uri":"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0304387820301905#appsec1","citation":"Islam, Asad, Wang-Sheng Lee, and Aaron Nicholas. 2021. \"The Effects of Chess Instruction on Academic and Non-cognitive Outcomes: Field Experimental Evidence from a Developing Country.\" Journal of Development Economics. Supplementary data (Appendix A): https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0304387820301905#appsec1."},{"name":"Data and Code for: Does Patient Demand Contribute to the Overuse of Prescription Drugs? (Lopez, Sautmann, and Schaner 2022)","note":"File location: external_data_code\/AEJApplied\/Lopez et al 2020\/. Original replication data and code for the underlying AEJ:Applied field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E126722V1","citation":"Lopez, Carolina, Anja Sautmann, and Simone Schaner. 2022. \"Data and Code for: Does Patient Demand Contribute to the Overuse of Prescription Drugs?\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E126722V1."},{"name":"Data for: Information, Technology, and Market Rewards (Magnan et al. 2021)","note":"File location: external_data_code\/JDE\/Magnan et al\/. Original replication data and code for the underlying JDE field experiment, redistributed as part of this deposit via Mendeley Data; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.17632\/y3tys8bfrd.1","citation":"Magnan, Nicholas, Vivian Hoffmann, Nelson Opoku, Gissele Gajate Garrido, and Daniel Kanyam. 2021. \"Data for: Information, Technology, and Market Rewards: Incentivizing Aflatoxin Control in Ghana.\" [dataset]. Mendeley Data, V1. https:\/\/doi.org\/10.17632\/y3tys8bfrd.1."},{"name":"Data for: Using Household Grants to Benchmark Cost Effectiveness (McIntosh and Zeitlin 2025)","note":"File location: external_data_code\/JDE\/McIntosh and Zeitlin\/. Original replication data and code for the underlying JDE field experiment, redistributed as part of this deposit via a public OSF deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"No License","uri":"https:\/\/doi.org\/10.17605\/OSF.IO\/YRH4E","citation":"McIntosh, Craig, and Andrew Zeitlin. 2025. \"Using Household Grants to Benchmark the Cost Effectiveness of a USAID Workforce Readiness Program.\" Journal of Development Economics. OSF, September 2025. https:\/\/doi.org\/10.17605\/OSF.IO\/YRH4E."},{"name":"Data and Code for: LinkedIn(to) Job Opportunities (Wheeler et al. 2022)","note":"File location: external_data_code\/AEJApplied\/Wheeleretal2022\/. Original replication data and code for the underlying AEJ:Applied field experiment, redistributed as part of this deposit; re-analyzed to produce one of the 17 treatment-effect estimates in the meta-analytic dataset.","access_type":"Data is publicly available and included in the reproducibility package.","license":"Creative Commons Attribution 4.0 International (CC BY 4.0)","license_uri":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/","uri":"https:\/\/doi.org\/10.3886\/E125461V1","citation":"Wheeler, Laurel, Robert Garlick, Eric Johnson, Patrick Shaw, and Marissa Gargano. 2022. \"Data and Code for: LinkedIn(to) Job Opportunities: Experimental Evidence from Job Readiness Training.\" [dataset]. American Economic Association; Inter-university Consortium for Political and Social Research. https:\/\/doi.org\/10.3886\/E125461V1."},{"note":"File locations: derived_data\/Dataset.xlsx, derived_data\/dataset_updated.dta, derived_data\/JournalCountData.dta. (1) Dataset.xlsx: authors' hand-built workbook, one sheet per study, containing re-estimated treatment effects from each of the 17 field-experiment papers; feeds dataset_updated.dta via Dofiles\/1. Prepare data.do, with the column-letter to variable-name crosswalk documented in Dofiles\/1a. rename.do. (2) dataset_updated.dta: cleaned analysis dataset of 743 treatment-effect estimates by 138 variables, derived by the authors from Dataset.xlsx; input to all main-text and appendix tables and figures. (3) JournalCountData.dta: original dataset compiled by the authors via manual full-text search of 10 journals for field-experiment papers using PDS Lasso, 2019-2025; input to Figure 1. All three are fully documented in codebook.md.\n","idno":"Authored\/Derived Datasets for Meta-Analysis","access_type":"Data is included in the reproducibility package.","citation":"Cilliers, Jacobus, Nour Elashmawy, and David McKenzie. 2026. \"Authored\/Derived Datasets for Meta-Analysis of 17 Field Experiments\" [dataset]. Authors' compilation, in Data and Code for: Using Post-Double Selection Lasso in Field Experiments. "}],"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: 32.0 GB","reproduction_instructions":"To reproduce the findings in this paper, a replicator must update the working directory in line 28 of the do-file `0. Set globals`, and run it."},"datacite":{"creators":[{"givenName":"David","familyName":"McKenzie","nameType":"Personal","affiliation":[{"name":"World Bank","affiliationIdentifier":"https:\/\/ror.org\/00ae7jd04","affiliationIdentifierScheme":"ROR","schemeUri":"https:\/\/ror.org"}]},{"givenName":"Jacobus","familyName":"Cilliers","nameType":"Personal","affiliation":[{"name":"Georgetown University","affiliationIdentifier":"https:\/\/ror.org\/05vzafd60","affiliationIdentifierScheme":"ROR","schemeUri":"https:\/\/ror.org"}]},{"givenName":"Nour","familyName":"Elashmawy","nameType":"Personal","affiliation":[{"name":"World Bank","affiliationIdentifier":"https:\/\/ror.org\/00ae7jd04","affiliationIdentifierScheme":"ROR","schemeUri":"https:\/\/ror.org"}]}],"titles":[{"lang":"en","title":"Reproducibility package for Using Post-Double Selection Lasso In Field Experiments"},{"title":"PP_WLD_2026_544","titleType":"Other"}],"publisher":"World Bank","publicationYear":"2026","types":{"resourceType":"Reproducibility package","resourceTypeGeneral":"Other"},"url":"https:\/\/reproducibility.worldbank.org\/index.php\/catalog\/study\/PP_WLD_2026_544","language":"en"},"tags":[{"tag":"DOI"},{"tag":"Open Code"},{"tag":"Open Data"}],"schematype":"script"}