All study GPs, including control GPs, continued to receive all other activities from the MFI. The intervention began in February 2015. Care was taken throughout the study period to ensure that the integrity of the research design was preserved. Authors conducted briefing sessions with the branch staff of the MFI before the start of the intervention, provided a pictorial reminder of the GPs where sanitation credit could not be offered, and monitored the disbursement of sanitation credit to control GPs using the MFI’s administrative monitoring system. As a result, contamination of the control group was very limited: a small number of loans was given out in the control group a few months after intervention roll-out, but this was swiftly stopped once noticed by the research team.

# **3.2 Data**

Our analysis draws on three sources of data. The first is an extensive household survey collected by the authors. This is linked with administrative loan data from the MFI partner. The final source of data is credit bureau reports, providing information on loans taken by sampled clients from all micro-finance providers in the study areas.

## **3.2.1 Primary Survey Data**

A survey on a sample of clients that had been active at the time of the roll-out in February 2015, and their households, was conducted in the period August to September 2017, about 2.5 years after sanitation loans were first made available. 2,841 clients (on average 24 per GP) were interviewed by a survey company (with interviewers blind to the outcome of the randomisation): 1,253 in the treatment and 1,588 in the control group.<sup>17,18</sup> Overall, we sampled around 75 percent of all clients active at the time of the intervention launch. Our sampling strategy focused on including clients from the same lending centre (kendra), in order to allow us to collect information on joint liability groups. Though it is not a random sample of clients, our high sampling rate ensures that the obtained sample is mostly representative of clients active in February 2015.<sup>19</sup> The household survey, asked of the household head, collected detailed information on household demographics, labour supply, and borrowing from formal and informal sources. In addition, a separate client survey elicited information on a number of different dimensions of her joint liability group, and interactions with the micro-finance provider. Detailed information on sanitation investment was also collected, including that on type of toilet, construction date and costs, and toilet usage. The information on the construction date allows us to obtain a retrospective measure of toilet ownership before the start of the

> 17For a sub-sample of these households, we have baseline data collected before the intervention began. We use this data to verify sample balance pre-intervention as discussed in detail in the project’s baseline report (available on request).

> 18Around 6 percent of sampled households, balanced across treated and control GPs, could not be interviewed because of refusals or lack of availability, and were replaced with back-up respondents.

> 19Simple t-tests comparing the characteristics of the obtained sample with the population of active clients reveal that the samples are similar on most observed characteristics other than small differences in the proportion of clients from backward castes, and age of the client. In particular, the sample includes fewer clients from backward castes and younger clients than the population of active clients. These results are available on request.

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