Today, hard-won progress is at risk.
In past decades, the world has made important gains in reducing poverty and creating opportunities for people and families to thrive. Behind these gains lies a strong foundation of economic growth, political will, smart investments, innovation, and a growing commitment to use data and evidence to inform policy. But existential challenges remain.
700 million people still live in extreme poverty. 42 million people in the United States live below the poverty line. Clean water, basic health care, and stable employment remain out of reach for many. Budgets are tight and foreign assistance is being cut, raising urgent questions about the future.
With fewer resources, the stakes are higher—but so is the potential for impact if we focus on solutions that are both effective and cost-effective. Data and evidence can help prioritize programs that truly make a difference.
This Evidence Effect page and accompanying blog series share what we have learned about improving the lives and livelihoods of people who are experiencing poverty. We discuss how these lessons have changed thinking, investments, and people's lives. This page offers powerful examples of effective development programs that reflect these lessons.
As we enter a new era marked by tighter budgets, growing inequality, and intensifying scrutiny, our hope is that these ideas contribute to debates and decisions on the future of development spending.
Evidence for more effective social policy in Europe and North America
Generating rigorous evidence on the effectiveness of programs designed to reduce poverty is not just the work of lower and middle-income countries. Countries across Europe and North America are also grappling with how to best tackle deep-rooted and pressing social challenges. These include bolstering social safety nets and better targeting social protection measures, improving access to quality education, helping citizens find employment opportunities, promoting safer communities, and adapting to climate change.
Evidence in action
The Evidence Effect highlights examples of life-changing programs that warrant more attention, investment, and consideration for scaling. Explore them below, drawn from more than 1,200 completed randomized evaluations led by researchers in our network.
How India used cap-and-trade to reduce pollution and improve health.
A dual strategy to alleviate poverty: Attaching conditions to cash transfers can provide immediate financial assistance while helping families invest in their children's future.
When low-income families receive cash with no strings attached, their lives improve in measurable ways.
Providing vulnerable households with accurate, timely information about their benefits can help improve access and increase government efficiency.
Sharing key information with parents and students can improve attendance, effort, and learning.
Providing regular deworming pills for children helps them stay in school, learn more, and earn more as adults.
A child’s earliest years shape lifelong outcomes. To boost children’s development, invest in programs that help parents interact with babies and toddlers in stimulating ways.
Meeting children where they are helps them catch up in school.
Many more people use products like mosquito nets, water-purifying chlorine tablets, and deworming pills when they are free.
The objectives of aid are often unclear.... Reaffirming the most basic principle would provide clarity: The goal should be to invest in projects that will have the largest impact on the quality of life of poor people around the world.
—Abhijit Banerjee and Esther Duflo, The Financial Times, March 2025
Read more about The Evidence Effect
Discover more perspectives from the J-PAL network
Radical simplification: A practical way to get more out of limited foreign assistance budgets
Center for Global Development
The Future of U.S. Foreign Aid: A series of virtual conversations
Harvard Center for International Development
Esther Duflo, Nobel laureate: 'Development aid is not a waste of public money'
Le Monde
Photos:
(1) Two farmers uproot rice seedlings for transplantation during monsoon season in India. Credit: Shutterstock.com
(2) A woman laughs as an enumerator measures her height in her home in Borong, East Nusa Tenggara, Indonesia. The measurement was part of an impact evaluation of an information campaign focused on preventing malnutrition. Credit: Miranda Putri, J-PAL
(3) Credit: Official, Shutterstock.com