This paper demonstrates the acute sensitivity of education program effectiveness to the choices of inputs and outcome measures, using a randomized evaluation of a mother-tongue literacy program. The program raises reading scores by 0.64 SD and writing scores by 0.45 SD. A reduced-cost version instead yields statistically insignificant reading gains and some large negative effects (−0.33 SDs) on advanced writing. We combine a conceptual model of education production with detailed classroom observations to examine the mechanisms driving the results; we show they could be driven by the program initially lowering productivity before raising it and potentially by missing complementary inputs in the reduced-cost version.

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Author notes

We thank John DiNardo, Paul Glewwe, David Lam, Jeff Smith, Lant Pritchett, Jake Vigdor, Susan Watkins, and seminar audiences at Michigan, Johns Hopkins, Université Paris-Dauphine, Minnesota, CSAE, Wilfrid Laurier University, CIES, the ESRC-DFID Poverty Conference, and London Experimental Week for comments and suggestions. We also thank Victoria Brown, Bernadette Jerome, Benson Ocan, and the rest of the Mango Tree staff. Funding was provided by the Hewlett Foundation, ESRC-DFID, an anonymous donor, and the University of Michigan's Rackham Graduate School. All mistakes and omissions are our own. The online appendix is available here.

A supplemental appendix is available online at https://doi.org/10.1162/rest_a_00911.

Supplementary data