DRI Working Paper No. 92
By David Roodman and Jonathan Morduch

The Impact of Microcredit on the Poor in Bangladesh: Revisiting the Evidence
We replicate and re-analyze the most influential study of microcredit impacts (Pitt and Khandker, 1998). That study was celebrated for showing that microcredit reduces poverty, a much hoped-for possibility (though one not confirmed by recent randomized controlled trials). We show that the original results on poverty reduction disappear after dropping outliers, or when using a robust linear estimator. Using a new program for estimation of mixed process maximum likelihood models, we show how assumptions critical for the original analysis, such as error normality, are contradicted by the data. We conclude that questions about impact cannot be answered in these data.