Esther Duflo reminiscenses

I first contacted Esther (and Abhijit) in 2006, when I wanted to write a New York Times column on their RCT work in India, specifically Hyderabad.  They were both extremely welcoming of my inquiries and did everything possible to give me a chance to observe their work up close.

I ended up traveling to Hyderabad, India, and spent a whole day with their RCT program in the field.  Annie Duflo, Esther’s sister, was gracious enough to travel with me around the city for an entire day, visiting the meetings where the women would show up to receive loans, and talking with the loan suppliers.  Overall I was astonished at how well-organized the work was, and how sophisticated the on-the-ground implementers were.  This was really work very carefully done.

Then, in 2013, seven years later, Banerjee and Duflo and co-authors Glennerster and Kinnan created a paper with the core results from the experiment, here is one version of the abstract:

This paper reports results from the randomized evaluation of a group lending microcredit program in Hyderabad, India. A lender worked in 52 randomly selected neighborhoods, leading to an 8.4 percentage point increase in takeup of microcredit. Small business investment and profits of pre-existing businesses increased, but consumption did not significantly increase. Durable goods expenditure increased, while “temptation goods” expenditure declined. We found no significant changes in health, education, or women’s empowerment. Two years later, after control areas had gained access to microcredit but households in treatment area had borrowed for longer and in larger amounts, very few significant differences persist.

Along with some (broadly consistent) results from Dean Karlan, this became one of the definitive papers on the effects of micro-credit.  It meant that micro-credit is OK, but not the cure for poverty.  That had a big subsequent impact on both policy and philanthropy.

You might have thought they would rest there, but no, they kept on looking at the data more deeply and over additional years, hoping to learn yet more from the experiment.  And just this last week, a new paper came out, modifying the earlier results, based on more years of data.  Here is the new abstract and paper (with Breza and Kinnan):

Can microcredit help unlock a poverty trap for some people by putting their businesses on a different trajectory? Could the small microcredit treatment effects often found for the average household mask important heterogeneity? In Hyderabad, India, we find that “gung ho entrepreneurs” (GEs), households who were already running a business before microfinance entered, show persistent benefits that increase over time. Six years later, the treated GEs own businesses that have 35% more assets and generate double the revenues as those in control neighborhoods. We find almost no effects on non-GE households. A model of technology choice in which talented entrepreneurs can access either a diminishing-returns technology, or a more productive technology with a fixed cost, generates dynamics matching the data. These results show that heterogeneity in entrepreneurial ability is important and persistent. For talented but low-wealth entrepreneurs, short-term access to credit can indeed facilitate escape from a poverty trap.

That is a pretty stunning extension of the original results, bravo to all hands involved!  Rust never sleeps, and in the hands of Banerjee and Duflo, neither does science.