Open defecation is a significant public health issue that causes 280,000 deaths from diarrheal disease per year. One billion people, or about 15% of the world’s population, currently practice open defecation, and another 1.5 billion people lack access to adequate sanitation.
In the study “Encouraging Sanitation Investment in the Developing World: A Cluster-Randomized Trial,” researchers randomly assigned 380 rural communities in Bangladesh to receive one of several programs aimed at increasing toilet ownership: a behavior change program educating villagers on the health benefits of using a toilet and encouraging community action; a combination of the behavior change program and a subsidy to buy a toilet; a program connecting villagers with suppliers providing information on toilet quality and availability; or a combination of the behavior change, subsidy, and supplier programs. A control group received no intervention.
“Combining behavior change programming with subsidies targeted to the poor is the only strategy that leads to significant increases in toilet investment and to significant decreases in open defecation,” says Ahmed Mushfiq Mobarak, a development economist at the Yale School of Management and lead author of the study.
The behavior change plus subsidy program increased toilet access by 9.4% relative to the control group; increased ownership by 20%, suggesting that some households that had been sharing toilets moved to individual ownership; and reduced open defecation by 22%. The behavior change program alone had no effect on toilet ownership, nor did the supplier intervention.
The results also show that the decision to invest in a toilet happens at the community level. In the study, subsidized communities were randomly divided not only by which households received subsidies, but also by what percentage of the community received a subsidy. Subsidizing the majority of households in a community increased toilet ownership among both subsidized households and their unsubsidized neighbors, suggesting that investment decisions are interlinked across neighbors.
“Subsidies are not as effective when the programs are targeted to individuals,” says Mobarak. “When a lot of people are subsidized together, that’s when individuals actually move. It’s more effective to go into a village and run programs that target the whole community jointly, and pay attention to the fact that people’s investment decisions are interlinked.”
The researchers hypothesize that giving subsidies to many people in a community may change social norms. Or it may be that when many households invest in toilets at the same time, the environment becomes sufficiently clean, and people see the benefit of investing in a toilet. Whereas if many people are defecating in the open, the risk of getting sick still exists even for toilet owners, making a toilet not worth the cost.
Mobarak says that the findings from Bangladesh offer timely lessons for India, where toilet access is an even greater public policy concern, with 55% of the population defecating in the open. Indian Prime Minister Narendra Modi, who campaigned on the slogan “Toilets first, temples later,” has pledged to put a toilet in every Indian household by 2019 as part of his Clean India Campaign.
“India has the budget; now they have to spend it effectively. Our research offers insight on how to do that to get results,” says Mobarak.
“Encouraging Sanitation Investment in the Developing World: A Cluster-Randomized Trial,” by Ahmed Mushfiq Mobarak (Yale School of Management), James Levinsohn (Yale School of Management and Yale’s Jackson Institute for Global Affairs), and Raymond Guiteras (University of Maryland) is published in the journal Science on April 16, 2015. The research was conducted in partnership with Innovations for Poverty Action, VERC, and WaterAid Bangladesh with support from the Bill & Melinda Gates Foundation.