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Do Differences in the Scale of Irrigation Projects Generate Different Impacts on Poverty and Production?


  • Andrew Dillon

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    • Andrew Dillon is with the International Food Policy Research Institute, 2033 K St. NW Washington, DC 20006, USA. E-mail: for correspondence. Financial support for the 2006 data collection was provided by the Projet du Développement de la Zone Lacustre – Phase II of the International Fund for Agricultural Development (IFAD), the Programme Mali-Nord (GTZ/KfW), the Strategies and Analysis for Growth and Access program (Cornell University and Clark Atlanta University), the Einaudi Center at Cornell University and the International Food Policy Research Institute (IFPRI). These data could not have been collected without the substantial assistance of Karin Dillon, Abdourhamane Maiga, Nouhou Idrissa Maiga, Mamadou Nadio, a dedicated team of survey enumerators and the helpful cooperation of the residents of the Zone Lacustre. The author gratefully acknowledges the valuable comments and suggestions from Christopher Barrett, Kaushik Basu, Daniel Gilligan, John Hoddinott, David Sahn and Xiaobo Zhang on earlier versions of this article during his dissertation as well as several anonymous reviewers. Rachel Gordon provided excellent research assistance. All errors remain the responsibility of the author.


This article investigates differences in household production and consumption among small- and large-scale irrigators to assess whether the scale of an irrigation project increases household welfare in Mali. Much of the evidence of the impact of irrigation does not use counterfactual analysis to estimate such impact or distinguish between the scale of the irrigation projects to be evaluated. In the dataset collected by the author, both a large-scale irrigation project and small-scale projects are used to construct counterfactual groups. Propensity score matching is used to estimate the average treatment effect on the treated for small and large irrigators relative to non-irrigators on agricultural production, agricultural income and consumption per capita. Small-scale irrigation has a larger effect on agricultural production and agricultural income than large-scale irrigation, but large-scale irrigation has a larger effect on consumption per capita. This suggests that market integration and non-farm externalities are important in realising gains in agricultural surplus from irrigation.