Encouraging Sanitation Investment in the Developing World: A Cluster-Randomized Trial

Poor sanitation contributes to morbidity and mortality in the developing world, but there is disagreement on what policies can increase sanitation coverage. To measure the effects of alternative policies on investment in hygienic latrines, we assigned 380 communities in rural Bangladesh to different marketing treatments—community motivation and information; subsidies; a supply-side market access intervention; and a control—in a cluster-randomized trial. Community motivation alone did not increase hygienic latrine ownership (+1.6 percentage points, p=0.43), nor did the supply-side intervention (+0.3 percentage points, p=.90). Subsidies to the majority of the landless poor increased ownership among subsidized households (+22.0 percentage points, p<.001) and their unsubsidized neighbors (+8.5 percentage points, p=.001), which suggests investment decisions are interlinked across neighbors. Subsidies also reduced open defecation by 14 percentage points (p<.001).

环境卫生不佳会加剧发展中国家的发病与死亡负担，但学界对于何种政策能够有效提升环境卫生普及率仍存在争议。为评估不同政策对卫生厕所（hygienic latrines）投资的影响，我们开展了一项整群随机试验（cluster-randomized trial），将孟加拉国农村地区的380个社区随机分配至四类推广干预组与对照组：社区动员与信息宣传组、补贴组、供给侧市场准入干预组，以及对照组。仅开展社区动员未显著提升卫生厕所拥有率（提升1.6个百分点，p=0.43），供给侧市场准入干预亦未产生显著效果（提升0.3个百分点，p=0.90）。针对绝大多数无地贫困人口的补贴政策，不仅使受补贴家庭的卫生厕所拥有率提升22.0个百分点（p<0.001），还使其未获补贴的邻里的拥有率提升8.5个百分点（p=0.001），这表明邻里间的卫生设施投资决策存在相互关联。此外，补贴政策还使露天排便（open defecation）行为减少14个百分点（p<0.001）。