In 2006, the World Bank’s Water and Sanitation Program (WSP) launched the Global Scaling Up Rural Sanitation program<sup>7</sup> to support local and national governments in India, Indonesia, and Tanzania to provide sanitation at scale. The program focused on learning how to combine the approaches of CLTS, behavior change communications, and social marketing of sanitation to generate sanitation demand and strengthen the supply of sanitation products and services at scale. In India, WSP supported efforts in rural Madhya Pradesh (MP) and Himachal Pradesh (HP) to strengthen TSC implementation.

WSP incorporated a cluster-randomized impact evaluation in Madhya Pradesh to gather rigorous evidence of the effectiveness of the TSC.<sup>8</sup> The evaluation was designed to fill three research gaps in the rural sanitation sector that, if filled, would help guide future implementation practice: (1) lack of randomized evaluations; (2) lack of objective outcome measures (including health outcomes); and (3) lack of evaluations of large-scale programs. The objectives of the evaluation were to measure the effect of the TSC on toilet coverage, open defecation, water quality, and child health (diarrheal disease, intestinal parasite infections, anemia, and growth). We hypothesized that the program would increase toilet coverage and reduce open defecation. We further hypothesized that the program would improve water quality by reducing the quantity of feces in the environment that could contaminate shallow groundwater aquifers or water distribution networks. The reduced load of enteric pathogens in the environment may also reduce transmission through flies, which are well-established vectors for enteric pathogens [10–12]. Conditional on improvements in these intermediate outcomes, we hypothesized that children < 24 months at enrollment in intervention villages would have a lower prevalence of diarrhea, intestinal parasite infections, and anemia when measured after the intervention. Finally, we hypothesized that the program would improve average weight-for-age and height-for-age in these young children as a result of fewer symptomatic and asymptomatic enteric infections [13– 17].

Our research contributes to a small body of literature on the effectiveness of community demand driven, large-scale sanitation programs. Despite widespread delivery of large-scale sanitation programs that incorporate CLTS-like approaches, we are aware of few published, independent evaluations of them. A randomized controlled trial of TSC in Orissa, India found that the program – a combination of CLTS tools for behavior change and hardware subsidies to poorer households – led to a 19 percentage point increase in toilet ownership (32% v. 13%) in 2006 after 5-7 months of implementation [18]. In Zimbabwe, an observational study of the Participatory Hygiene and Sanitation Transformation (PHAST) campaign that combined elements of CLTS with subsidized hardware increased toilet ownership from 2% to 43% [19]. In 2004, a CLTS campaign in Ethiopia that constructed over 89,000 latrines found that 87% of 160

> 7 For more information on Global Scaling Up Rural Sanitation, see www.wsp.org/scalingupsanitation.

> 8 The study was initially designed for two independent sites in Madya Pradesh (MP) and in Himachal Pradesh (HP). Due to delays on baseline survey preparation and the impossibility to hold implementation in the control areas in the state of HP, it was decided that the final impact evaluation only included the state of MP.

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