We use a randomized controlled trial (RCT) to investigate social effects on the adoption of mechanized desludging. First, we will offer randomly selected neighborhoods subsidized desludging services coupled with various social pressure treatments to measure direct social effects.
We will construct 400 groups of twelve neighboring households each. These neighborhoods will be far enough apart that, in general, their sanitation decisions will not affect one another and the households will not know one another. In our 400 selected neighborhoods, each neighborhood will include 10 randomly chosen treated households and 2 untreated households; these 2 untreated households will allow us to measure indirect spillovers.
We will first conduct a baseline survey of demographic information, including household composition, education, health, membership and participation in associations and cooperatives, and savings habits. We will also collect GPS data on the locations of the households.
We then conduct a second survey on willingness to pay for improved sanitation with the household member who is in charge of making decisions regarding desludging ("the decider"). The decider survey will cover savings and loans, wealth and durable assets, brief questions on income and spending, sanitation practices, and social networks. The social network component of the survey will include questions asking who in their neighborhood they talk with about waste disposal, who they would choose to lead a neighborhood sensitization on health, who is a member of the same association or cooperative as them, from whom they would borrow or to whom they would lend money, who they did borrow from or lend to within the past year, with whom they are related, which households use mechanized desludging, and where each household dumps its sludge.
At the time of the second survey, in the 10 treatment households, we will offer the decider his randomly assigned treatment. There are several treatment arms (please see experimental design) but one main treatment involves randomizing discounts of different sizes to households that sign up for a subscription of two desludgings, and randomizing whether this discount is private or public information.
At the end of the decider survey, households in the "deposit" group which would like to sign up for the subscription will be asked to pay a deposit of roughly US$6 – an amount equal to the respondent's participation gift. The deposit will be credited towards the second desludging, and will be unavailable to them until the end of the nine-month subsidy period. After the subsidy period ends, they will have the option to continue using the subscription for an unsubsidized third desludging depending on the interest of the Senegalese Ministry of Sanitation in continuing the program following the main research period.
After the year in which treated households have access to subsidized desludgings, we will re-interview both the 4000 treated households and the 800 untreated households, allowing us to measure their sanitation practices and relationships with neighbors.