Are government and nonprofit programs actually improving lives like they claim to? We don’t always know, but economist Rachel Glennerster has been working over the last three decades to figure out the best ways to ensure that they do.

Before the recent movement to try to bring rigor to global antipoverty programs, it was more difficult to tell whether a program was actually making a difference, or if improvements in lives were just a result of the world getting better over time. Glennerster — alongside other economists like the 2019 Nobel Prize winners Abhijit Banerjee, Esther Duflo, and Michael Kremer — helped normalize the use of evidence in global development and other anti-poverty work.

This has been predominantly through the use of randomized controlled trials (RCTs). An RCT randomizes which people receive a certain program or not — for example, a cash transfer for a vaccine, or an agricultural training program — and compares the groups to see if the program had an effect on people’s lives.

A key part of figuring out which problems to solve, Glennerster argues, is understanding which questions to ask and how to answer them. “A lot of development programs just fail because they’re trying to solve a problem that doesn’t exist,” she said on an 80,000 Hours podcast in 2018. In keeping with that, Glennerster has also touted methodological nimbleness as virtue — that other methods beyond RCTs might offer better answers for some of our big questions. “I think the right way to see things is you have a toolbox of ways to answer questions, and the right tool depends on the question that you’re asking,” she said.

Since the early 2000s, Glennerster’s career has spanned almost every aspect of research and practice: she has worked for the UK government, the Harvard Institute for International Development, and the International Monetary Fund. She’s led RCTs on health, education, gender, agriculture, conflict, and more — looking at whether policy changes have measurably improved people’s lives.

Notably, Glennerster spent 13 years as the executive director of the Abdul Latif Jameel Poverty Action Lab (J-PAL), a key leader in popularizing RCTs in development economics. During her time at J-PAL, she helped establish “Deworm the World,” a program that works with governments to provide over 1.3 billion school-based deworming treatments in India, Kenya, Nigeria, Ethiopia, and Pakistan.

After J-PAL, Glennerster brought an evidence-based mindset to foreign aid. As chief economist of the UK’s Foreign, Commonwealth and Development Office (FCDO), she looked at the cost-effectiveness of different programs and recommended “smart buys” to improve global education, including teaching to students’ learning levels instead of age and investing in pre-primary education.

Glennerster finished her appointment at the FCDO in 2021 and is now a professor at the University of Chicago, where she’s continued her research on topics such as the Covid-19 vaccine supply and the effect of mass media on contraceptive use.

“I think there is an ethical imperative for people who are designing [programs] to think very hard about what the evidence says behind what they’re doing and to be aware that just having good intentions doesn’t always mean that you are doing good,” she told Harvard Law School’s The Practice. “You should take into account and think about your ethical responsibility to know what you’re doing before you intervene in other people’s lives.”