Foundations

Unconditional cash transfers raised average monthly household consumption from 158 to 193 dollars nine months after the transfers began. Johannes Haushofer and Jeremy Shapiro, 2016, Quarterly Journal of Economics. Source

School based deworming in Kenya cut school absenteeism by one quarter, and the health gains spilled over to untreated children in nearby schools. Edward Miguel and Michael Kremer, 2004, Econometrica. Source

When the Safelite Glass Corporation moved workers to piece rates, output per worker rose by 44 percent. Edward P. Lazear, 2000, American Economic Review. Source

After two years, students in schools where teachers earned bonuses averaging 3 percent of pay scored 0.27 standard deviations higher in math and 0.17 higher in language than students in control schools. Karthik Muralidharan and Venkatesh Sundararaman, 2011, Journal of Political Economy. Source

One year after communities began monitoring local health clinics with citizen report cards, deaths among children under five were 33 percent lower in treatment communities. Martina Björkman and Jakob Svensson, 2009, Quarterly Journal of Economics. Source

Raising the chance of a government audit on village road projects from 4 percent to 100 percent cut missing expenditures by about 8 percentage points. Benjamin A. Olken, 2007, Journal of Political Economy. Source

The gap in life expectancy between the richest 1 percent and the poorest 1 percent was 14.6 years for men and 10.1 years for women. Raj Chetty and co-authors, 2016, JAMA. Source

In 661,137 adults, even activity below the recommended weekly minimum came with a 20 percent lower risk of death, and 1 to 2 times the minimum came with a 31 percent lower risk. Hannah Arem and co-authors, 2015, JAMA Internal Medicine. Source

In about 250,000 sampled moments from 2,250 adults, minds were wandering 46.9 percent of the time, and people were less happy while wandering than while present, whatever they were doing. Matthew A. Killingsworth and Daniel T. Gilbert, 2010, Science. Source

In more than 450,000 survey responses, emotional well-being rose with income up to about 75,000 dollars a year and then stopped rising, even though life evaluation kept rising with income. Daniel Kahneman and Angus Deaton, 2010, Proceedings of the National Academy of Sciences. Source

Each standard deviation rise in reported purpose in life came with a 15 percent lower risk of death over the 14 years that followed, at every adult age. Patrick L. Hill and Nicholas A. Turiano, 2014, Psychological Science. Source

Only 17.2 percent of United States adults aged 25 to 74 met the criteria for flourishing, while 12.1 percent were languishing, and languishing adults faced nearly six times the risk of a major depressive episode that flourishing adults faced. Corey L. M. Keyes, 2002, Journal of Health and Social Behavior. Source

Across 225 studies, average examination scores rose by about 6 percent under active learning, and students in traditional lecture classes were 1.5 times more likely to fail. Scott Freeman and co-authors, 2014, Proceedings of the National Academy of Sciences. Source

One week after learning a passage, students who studied it once and took three memory tests remembered 61 percent of it, while students who studied it four times remembered 40 percent. Henry L. Roediger III and Jeffrey D. Karpicke, 2006, Psychological Science. Source

Readers rated the author of a text rewritten with shorter, simpler words as more intelligent (4.80 versus 4.26 on a 7 point scale) than the author of the same text written with needlessly long words. Daniel M. Oppenheimer, 2006, Applied Cognitive Psychology. Source

Patients reading at or below the sixth grade level were 3.4 times less likely to interpret prescription warning labels correctly, and short single step instructions were understood better by readers at every level. Terry C. Davis and co-authors, 2006, Journal of General Internal Medicine. Source

Professional interpreters improved the quality of care for patients with limited English more than ad hoc interpreters did, bringing care close to the level patients without language barriers receive. Leah S. Karliner, Elizabeth A. Jacobs, Alice Hm Chen, and Sunita Mutha, 2007, Health Services Research. Source

In a preregistered experiment with 453 professionals, access to ChatGPT cut average time on writing tasks by 40 percent and raised output quality by 18 percent, and the gap between stronger and weaker workers shrank. Shakked Noy and Whitney Zhang, 2023, Science. Source

Among 5,179 customer support agents, an AI assistant raised issues resolved per hour by 14 percent on average and by 34 percent for novice and low skilled workers, with minimal change for the most experienced. Erik Brynjolfsson, Danielle Li, and Lindsey R. Raymond, 2025, Quarterly Journal of Economics. Source

Across 148 studies covering 308,849 people, those with stronger social relationships had a 50 percent greater likelihood of survival, an effect the authors rank alongside quitting smoking. Julianne Holt-Lunstad, Timothy B. Smith, and J. Bradley Layton, 2010, PLOS Medicine. Source

In a controlled virus exposure experiment with 276 volunteers, people with only 1 to 3 types of social ties had an adjusted relative risk of 4.2 for catching a cold compared with people with 6 or more types of ties. Sheldon Cohen and co-authors, 1997, JAMA. Source

Among 240 players in a public goods game, 84.3 percent paid their own money to punish free riders at least once, and cooperation rose steadily when punishment was allowed. Ernst Fehr and Simon Gächter, 2002, Nature. Source

Across 49 self governing forest user groups in Ethiopia, a group where 60 percent of members were conditional cooperators spent about 14 more hours a month patrolling than a group with none, and such groups kept more potential crop trees per hectare. Devesh Rustagi, Stefanie Engel, and Michael Kosfeld, 2010, Science. Source

Tracking about 126,000 story cascades shared by some 3 million people on Twitter, the team found false stories were 70 percent more likely to be retweeted than true ones and reached 1,500 people about six times faster. Soroush Vosoughi, Deb Roy, and Sinan Aral, 2018, Science. Source

In five experiments with more than 10,100 subjects across 52 contested issues, the researchers found zero factual corrections that made people believe a falsehood more strongly. Thomas Wood and Ethan Porter, 2019, Political Behavior. Source

Global crop demand is forecast to rise by 100 to 110 percent between 2005 and 2050. David Tilman, Christian Balzer, Jason Hill, Belinda L. Befort, 2011, Proceedings of the National Academy of Sciences. Source

Growing crops only for direct human consumption could raise available food calories by up to 70 percent and feed an additional 4 billion people. Emily S. Cassidy, Paul C. West, James S. Gerber, Jonathan A. Foley, 2013, Environmental Research Letters. Source

Across 46 studies, water, sanitation, and hygiene interventions cut diarrhoea risk, with relative risk estimates between 0.63 and 0.75. Lorna Fewtrell, Rachel B. Kaufmann, David Kay, Wayne Enanoria, Laurence Haller, John M. Colford Jr., 2005, The Lancet Infectious Diseases. Source

In developing regions, each 1 US dollar invested in water and sanitation returned between 5 and 46 US dollars, depending on the intervention. Guy Hutton, Laurence Haller, Jamie Bartram, 2007, Journal of Water and Health. Source

Over two years, Housing First participants were in stable housing 71 percent of the time, compared with 29 percent for people receiving treatment as usual. Tim Aubry, Paula Goering, Scott Veldhuizen, Carol E. Adair, Jimmy Bourque, Jino Distasio, and coauthors, 2016, Psychiatric Services. Source

People in insulated homes in low income New Zealand communities had half the odds of reporting fair or poor health, an adjusted odds ratio of 0.50. Philippa Howden-Chapman, Anna Matheson, Julian Crane, Helen Viggers, Malcolm Cunningham, and coauthors, 2007, BMJ. Source

In low income renter families, being behind on rent was associated with worse caregiver and child health. This is an observational study, so it shows association, not cause. Megan Sandel, Richard Sheward, Stephanie Ettinger de Cuba, Sharon M. Coleman, Deborah A. Frank, Mariana Chilton, Maureen Black, Timothy Heeren, Justin Pasquariello, Patrick Casey, Eduardo Ochoa, and Diana Cutts, 2018, Pediatrics. Source

In rural South Africa, household electrification raised female employment by 9 to 9.5 percentage points within five years. Taryn Dinkelman, 2011, American Economic Review. Source

In rural India, solar microgrids raised household electrification by 29 to 36 percentage points within a year but added only 0.99 to 1.42 hours of power a day and gave no clear gain in work or study. Michaël Aklin, Patrick Bayer, S. P. Harish, Johannes Urpelainen, 2017, Science Advances. Source

Two years of weekly home visits for growth stunted toddlers in Jamaica raised their earnings by 25 percent when they were checked 20 years later. Paul Gertler, James Heckman, Rodrigo Pinto, Arianna Zanolini, Christel Vermeersch, Susan Walker, Susan M. Chang, Sally Grantham-McGregor, 2014, Science. Source

By age 28, children from low income Chicago families in the Child-Parent Center program had health insurance coverage of 75.9 percent, compared with 63.9 percent in the comparison group. Arthur J. Reynolds, Judy A. Temple, Suh-Ruu Ou, Irma A. Arteaga, Barry A. B. White, 2011, Science. Source

Children who received the Abecedarian early childhood program had markedly better heart and metabolic health in their mid thirties, especially the men. Frances Campbell, Gabriella Conti, James J. Heckman, Seong Hyeok Moon, Rodrigo Pinto, Elizabeth Pungello, and Yi Pan, 2014, Science. Source

Across the studies reviewed, loneliness raised the likelihood of death by 26 percent, social isolation by 29 percent, and living alone by 32 percent. Julianne Holt-Lunstad, Timothy B. Smith, Mark Baker, Tyler Harris, David Stephenson, 2015, Perspectives on Psychological Science. Source

Twelve changeable risk factors account for around 40 percent of dementia cases worldwide, so those cases could in theory be prevented or delayed. Gill Livingston, Jonathan Huntley, Andrew Sommerlad, David Ames, Clive Ballard, and coauthors, 2020, The Lancet. Source

A five month home program pairing occupational therapy, nursing, and a handyman reduced disability in low income older adults. Sarah L. Szanton, Qian-Li Xue, Bruce Leff, Jack Guralnik, Jennifer L. Wolff, Elizabeth K. Tanner, Cynthia Boyd, Roland J. Thorpe, David Bishai, and Laura N. Gitlin, 2019, JAMA Internal Medicine. Source

Reablement, short intensive home rehabilitation aimed at the person's own goals, improved older adults' self perceived performance and satisfaction more than usual care, and the gain held at nine months. Hanne Tuntland, Mona Kristin Aaslund, Birgitte Espehaug, Oddvar Førland, and Ingvild Kjeken, 2015, BMC Geriatrics. Source

More than 1 billion people lived with a disability, and in OECD countries only 44 percent of people with disabilities were employed, against 75 percent of people without disabilities. World Health Organization and World Bank, 2011, World Health Organization and World Bank report. Source

Pooling 98 studies, the authors found that 31.7 percent of children with disabilities had experienced violence. Zuyi Fang, Ilan Cerna-Turoff, Cheng Zhang, Mengyao Lu, Jamie M. Lachman, Jane Barlow, 2022, The Lancet Child & Adolescent Health. Source

Across 15 developing countries, disability was significantly associated with higher multidimensional poverty, less schooling, lower employment, and higher medical spending in most countries. Sophie Mitra, Aleksandra Posarac, and Brandon Vick, 2013, World Development. Source

After mobile phones spread among Kerala fishers, their profits rose by 8 percent and the prices paid by consumers fell by 4 percent. Robert Jensen, 2007, The Quarterly Journal of Economics. Source

Access to mobile money in Kenya lifted 194,000 households, 2 percent of all households, out of poverty. Tavneet Suri, William Jack, 2016, Science. Source

Being held for just 3 days before trial raised the probability of a guilty finding by 14 percentage points. Will Dobbie, Jacob Goldin, Crystal S. Yang, 2018, American Economic Review. Source

White test applicants without a criminal record received callbacks for 34 percent of jobs, compared with 17 percent for white applicants with a record. Devah Pager, 2003, American Journal of Sociology. Source

Climate trends from 1980 to 2008 cut global maize production by 3.8 percent and wheat production by 5.5 percent compared with a world without those trends. David B. Lobell, Wolfram Schlenker, Justin Costa-Roberts, 2011, Science. Source

Across 384 locations, 7.71 percent of deaths were linked to temperatures outside the safest range, with cold linked to 7.29 percent and heat to 0.42 percent. Antonio Gasparrini, Yuming Guo, Masahiro Hashizume, and coauthors, 2015, The Lancet. Source

After hurricanes, insured households financed recovery mainly through their insurance while uninsured households leaned on friends and family, and insured households reported less financial strain and fewer unmet funding needs. Xuesong You and Carolyn Kousky, 2024, Journal of Risk and Insurance. Source

In trials with 10,495 people in six countries, 8 of 10 outcome measures still showed significant gains one year after the program ended. Abhijit Banerjee, Esther Duflo, Nathanael Goldberg, Dean Karlan, Robert Osei, William Parienté, Jeremy Shapiro, Bram Thuysbaert, Christopher Udry, 2015, Science. Source

California's paid family leave program doubled new mothers' use of maternity leave, and employed mothers of toddlers worked more hours afterward, with wage income rising by a similar amount. Maya Rossin-Slater, Christopher J. Ruhm, and Jane Waldfogel, 2013, Journal of Policy Analysis and Management. Source

The average price equivalent of migration barriers to the United States for low skill men was more than 13,700 dollars per worker per year. Michael A. Clemens, Claudio E. Montenegro, Lant Pritchett, 2019, The Review of Economics and Statistics. Source

One extra year of waiting for an asylum decision cut the later employment rate by 4 to 5 percentage points, a drop of 16 to 23 percent from the average rate. Jens Hainmueller, Dominik Hangartner, Duncan Lawrence, 2016, Science Advances. Source

When a father migrated to the United States earlier rather than later, his daughter's schooling in Mexico rose, while a father's migration inside Mexico showed no such effect. Francisca M. Antman, 2012, Journal of Population Economics. Source

Treating insomnia with digital cognitive behavioral therapy also reduced paranoia and hallucinations in university students. Daniel Freeman, Bryony Sheaves, Guy M. Goodwin, Ly-Mee Yu, Alecia Nickless, Paul J. Harrison, Richard Emsley, Annemarie I. Luik, Russell G. Foster, Vanashree Wadekar, Christopher Hinds, Andrew Gumley, Ray Jones, Stafford Lightman, Steve Jones, Richard Bentall, Peter Kinderman, Georgina Rowse, Traolach Brugha, Mark Blagrove, Alice M. Gregory, Leanne Fleming, Elaine Walklet, Cris Glazebrook, E. Bethan Davies, Chris Hollis, Gillian Haddock, Bev John, Mark Coulson, David Fowler, Katherine Pugh, John Cape, Peter Moseley, Gary Brown, Claire Hughes, Marc Obonsawin, Sian Coker, Edward Watkins, Matthias Schwannauer, Kenneth MacMahon, A. Niroshan Siriwardena, and Colin A. Espie, 2017, The Lancet Psychiatry. Source

High schools that start at 8:30 AM or later let most students sleep at least eight hours, and later starts were linked to better grades, attendance, and far fewer teen car crashes. Kyla L. Wahlstrom, Beverly J. Dretzke, Molly F. Gordon, Kristin Peterson, Katherine Edwards, and Julie Gdula, 2014, Center for Applied Research and Educational Improvement, University of Minnesota. Source

A treatment built specifically for complicated grief worked better than standard interpersonal psychotherapy. M. Katherine Shear, Ellen Frank, Patricia R. Houck, and Charles F. Reynolds III, 2005, JAMA. Source

Adding prize based contingency management to standard care lengthened continuous stimulant abstinence in community clinics. Nancy M. Petry, Jessica M. Peirce, Maxine L. Stitzer, Jack Blaine, John M. Roll, Allan Cohen, Jeanne Obert, Therese Killeen, Michael E. Saladin, Mark Cowell, Kimberly C. Kirby, Robert Sterling, Charlotte Royer-Malvestuto, John Hamilton, Robert E. Booth, Marilyn Macdonald, Marc Liebert, Linda Rader, Raynetta Burns, Joan DiMaria, Marc Copersino, Patricia Quinn Stabile, Ken Kolodner, and Rui Li, 2005, Archives of General Psychiatry. Source

Offering a commitment savings account that restricts withdrawals until a self set goal is met raised savings balances, even though only a minority opened one. Nava Ashraf, Dean Karlan, and Wesley Yin, 2006, Quarterly Journal of Economics. Source

Charging even a small price for insecticide treated bed nets cut uptake sharply, and people who got nets free were no less likely to use them. Jessica Cohen and Pascaline Dupas, 2010, Quarterly Journal of Economics. Source

Young adults whose debt was high relative to their assets reported more stress and depressive symptoms and had higher diastolic blood pressure. This is an observational study, so it shows association, not cause. Elizabeth Sweet, Arijit Nandi, Emma K. Adam, and Thomas W. McDade, 2013, Social Science and Medicine. Source

Children taught shapes through guided play learned more than children taught by direct instruction or left to free play, and the gain was still there a week later. Kelly R. Fisher, Kathy Hirsh-Pasek, Nora Newcombe, and Roberta M. Golinkoff, 2013, Child Development. Source

Ten weeks of group drumming improved depression, anxiety, social resilience, and wellbeing in mental health service users, and the gains held three months later. Groups were allocated by location rather than randomized, so the study is exploratory. Daisy Fancourt, Rosie Perkins, Sara Ascenso, Livia A. Carvalho, Andrew Steptoe, and Aaron Williamon, 2016, PLOS ONE. Source

In a comparative case study of three makerspaces, learning was embedded in the making itself: people identified problems, built models, applied skills, revised, and shared. This is a qualitative study; it reports no effect size. Kimberly Sheridan, Erica Rosenfeld Halverson, Breanne Litts, Lisa Brahms, Lynette Jacobs-Priebe, and Trevor Owens, 2014, Harvard Educational Review. Source

A health impact assessment estimates that building out Barcelona's full superblock plan would prevent hundreds of premature deaths a year. These are modeled estimates, not measured outcomes. Natalie Mueller, David Rojas-Rueda, Haneen Khreis, Marta Cirach, David Andrés, Joan Ballester, Xavier Bartoll, Carolyn Daher, Anna Deluca, Cynthia Echave, Carles Milà, Sandra Márquez, Joan Palou, Katherine Pérez, Cathryn Tonne, Mark Stevenson, Salvador Rueda, and Mark Nieuwenhuijsen, 2020, Environment International. Source

After a local newspaper closed, voters in the affected counties became more likely to vote a straight party ticket, as if the shared local information source was gone. Joshua P. Darr, Matthew P. Hitt, and Johanna L. Dunaway, 2018, Journal of Communication. Source

Group cognitive behavioral therapy and group pain education, both rewritten in plain language for low literacy patients, reduced pain and improved physical function more than usual care in low income clinics. Beverly E. Thorn, Joshua C. Eyer, Benjamin P. Van Dyke, Calia A. Torres, John W. Burns, Minjung Kim, Andrea K. Newman, Lisa C. Campbell, Brian Anderson, Phoebe R. Block, Bentley J. Bobrow, Regina Brooks, Toya T. Burton, Jennifer S. Cheavens, Colette M. DeMonte, William D. DeMonte, Crystal S. Edwards, Minjeong Jeong, Mazheruddin M. Mulla, Terence Penn, Laura J. Smith, and Deborah H. Tucker, 2018, Annals of Internal Medicine. Source

A scoping review maps how US public libraries already do health related work, from health information and linkage to services, and argues libraries are an underused community level resource for population health. A scoping review maps a field; it does not measure an outcome effect. Morgan M. Philbin, Caroline M. Parker, Mary Grace Flaherty, and Jennifer S. Hirsch, 2019, Journal of Community Health. Source

Community repair events extend product life, but the study finds the material and the social cannot be separated: repair builds attachment to things through tinkering, sharing, and care. This is a qualitative study; it reports no effect size. Maja van der Velden, 2021, Journal of Cleaner Production. Source