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Research related to:  Poverty

Substitution Bias and External Validity: Why an innovative anti-poverty program showed no net impact

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The net impact of development interventions can depend on the availability of close substitutes to the intervention. We analyze a randomized trial of an innovative anti-poverty program in South India which provides “ultra-poor” households with inputs to create a new, sustainable livelihood. We find no statistically significant evidence of lasting net impact on consumption, income or asset accumulation. Instead, income from the new livelihood substituted for earnings from wage labor. A very similar intervention made a large difference elsewhere in South Asia, however, where wage labor alternatives were less compelling. The analysis highlights the roles of substitution bias and dropout bias in shaping evaluation results and delimiting external validity.
Jonathan Morduch, Shamika Ravi, and Jonathan Bauchet

The Impact of Microcredit on the Poor in Bangladesh: Revisiting the Evidence

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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.
David Roodman and Jonathan Morduch

Poverty and Self-Control

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The absence of self-control is often viewed as an important correlate of persistent poverty. Using a standard intertemporal allocation problem with credit constraints faced by an individual with quasi-hyperbolic preferences, we argue that poverty damages the ability to exercise self-control. Our theory invokes George Ainslie’s notion of “personal rules,” interpreted as subgame-perfect equilibria of an intrapersonal game played by a time-inconsistent decision maker. Our main result pertains to situations in which the individual is neither so patient that accumulation is possible from every asset level, nor so impatient that decumulation is unavoidable from every asset level. Such cases always possess a threshold level of assets above which personal rules support unbounded accumulation, and a second threshold below which there is a “poverty trap” . . . 
B. Douglas Bernheim, Debraj Ray, and Sevin Yeltekin