贡献分析实践质量指南

Giel TonThomas DelahaisAndrew KolerosMarina Apgar IEG Methods and Evaluation Capacity Development Working Paper Series © 2026 International Bank for Reconstruction and Development / The World Bank1818 H Street NWWashington, DC 20433Telephone: 202-473-1000Internet: www.worldbank.org ATTRIBUTIONPlease cite the report as:Ton, Giel, Thomas Delahais, Andrew Koleros, and Marina Apgar.2026. Quality Guidance for Contribution Analysis in Practice.IEG Methods and Evaluation CapacityDevelopment Working Paper Series.Independent Evaluation Group. World Bank. MANAGING EDITORDiana M. Stanescu EDITING AND PRODUCTIONAmanda O’Brien GRAPHIC DESIGNLuísa Ulhoa This work is a product of the staff of The World Bank with external contributions. The findings,interpretations, and conclusions expressed in this work do not necessarily reflect the views ofThe World Bank, its Board of Executive Directors, or the governments they represent.The World Bank does not guarantee the accuracy of the data included in this work. The bound-aries, colors, denominations, and other information shown on any map in this work do not implyany judgment on the part of The World Bank concerning the legal status of any territory or theendorsement or acceptance of such boundaries. RIGHTS AND PERMISSIONSThe material in this work is subject to copyright. Because The World Bank encourages dissem- ination of its knowledge, this work may be reproduced, in whole or in part, for noncommercialpurposes as long as full attribution to this work is given. Any queries on rights and licenses, including subsidiary rights, should be addressed to WorldBank Publications, The World Bank Group, 1818 H Street NW, Washington, DC 20433, USA; fax:202-522-2625; e-mail: pubrights@worldbank.org. Quality Guidance forContribution Analysisin Practice Giel Ton, Thomas Delahais, Andrew Koleros,and Marina Apgar Independent Evaluation GroupMarch, 2026 AUTHOR AFFILIATIONS Giel Ton, research fellow at the Institute of Development Studies and codirector ofthe Centre for Development Impact.email:g.ton@ids.ac.uk Thomas Delahais, founding partner of Quadrant Conseil.email:tdelahais@quadrant-conseil.fr Andrew Koleros, principal researcher at Mathematica.email:dkoleros@mathematica-mpr.com Marina Apgar, research fellow at the Institute of Development Studies and codirec-tor of the Centre for Development Impact.email:m.apgar@ids.ac.uk QUALITY GUIDANCE FORCONTRIBUTION ANALYSIS IN PRACTICE Contribution analysis (CA)is an evaluation approach that critically assesses how an“intervention”1contributes to changes of interest. CA recognizes that various fac-tors and actors, other than or in addition to the intervention, typically play a role inexplaining how and why change happened—particularly in more complex situations.It thus provides a structured, iterative way to understand complex change processes,make sense of an intervention’s role in relation to these other factors and actors,and assess the intervention’s contributions. Initially developed by John Mayne (Mayne 2001), CA has substantially evolved overthe past 25 years as evaluators have adapted it to emerging evaluation contexts andchallenges (Nielsen and Lemire 2025). Its growing popularity, however, has led to adiversity in practice, resulting in some confusion among contemporary evaluatorsabout what CA actually entails, the types of contribution claims made, and how toassess quality. This document responds to the current state of CA practice by offering guidance tosupporthigh-quality application of contemporary CA. It aims to inform soundevaluative practice, promote greater consistency in application, and strengthencollective use of CA. The guidance is not intended to serve as an introduction to CA,but rather to support experienced evaluators in applying the approach, and may alsoinform commissioners about the features and conditions required for high-qualityCA. What these features and conditions look like in reality will be developed in moredetail and with practical examples in a companion methodology guide that will beavailable in 2026. This guidance is organized around the followingsix key steps of CA, which encom-pass two main phases—theory building and theory testing (figure1; Mayne 2019): 1.Set out the cause–effect issue to be addressed. 2.Develop a robust theory of change for the intervention and its pathways.3.Gather the existing evidence for the theory of change and contributionclaims.4.Assemble and assess the resulting contribution claims and the challengesto them.5.Seek out additional evidence.6.Revise and strengthen the contribution story. It also reflects the features that make CA distinctive from other approaches2—namely,that these steps are typically not applied sequentially, butiteratively(steps are 2This document benefited from the discussion with a community of CA practitionersthrough a participatory workshop held in April 2025 and a subsequent concept mappingexercise. The authors of this guidance are th