Rationale and Formative Research

The Nam Nalavazhvu intervention design leverages 2 years of mixed-method formative research which included 2 rounds of surveys with the following aims: (1) map social networks in similar communities and (2) systematically diagnose the collective behavior of toilet use with SNT. These sequential assessments were conducted concurrently in both Bihar and Tamil Nadu [26]. Specifically, the formative research comprised the following: a social network survey (n=3370) to understand the size, structure, and nature of social ties related to sanitation behaviors and ownership; 18 focus group discussions with men and women, including young unmarried women and older women to explore social and gender norms related to toilet construction and use; and a social norms survey (n=5052) to assess social beliefs, expectations, and determinants of open defecation.

As mentioned, the Nam Nalavazhvu intervention is based on the SNT, which highlights the role of social expectations and conditional preferences in guiding collective behaviors [25]. We drew on previous literature and investigated known social factors, such as preference for open defecation, perceived barriers related to toilet ownership and maintenance, and implications of social expectations of others in one’s community [32,33]. We measured social beliefs, along with empirical (what others in their community do) and normative expectations (beliefs about what others should do), related to toilet usage and used the results to assess if toilet use was a socially interdependent behavior in Indian communities. Using vignettes and regression analyses, we found that empirical expectations were a strong driver of toilet use, while normative expectations were not [26]. This suggested toilet use in this context was a “descriptive norm” or an interdependent behavior where beliefs of what most other people do influence one’s behavior [25]. This is consistent with other recent studies that reported empirical expectations as a significant psychosocial determinant for toilet ownership [11,15]. Based on these findings, we designed a theoretically grounded, evidence-based behavior change intervention. We will evaluate its effectiveness on the uptake of exclusive toilet use and maintenance through this randomized trial.