Experimental Design
Treatment will be assigned at the level of a water tank; that is, the government will assign water tanks to be repaired or restored in a certain phase or not until a later phase. In the first, non-experimental component of the study, the sample is composed of tanks that have already been taken up for repair or restoration. We identified a sample of 752 comparable treatment and control tanks from phases 1 and 2, stratified by Assembly Constituency (the lowest unit where decisions are made with regard to which tanks are to be selected under specific phase), using propensity score matching method. Phase 1 tanks, most of which have been restored as of summer 2016, served as treatment tanks, and phase 2 tanks, most of which have yet to be restored as of early 2017, served as control tanks. The observable variables on which the tanks were matched on included: a) observable tank characteristics such as the command area, catchment area, tank storage capacity, bund length, number of feeder and irrigation channels, b) estimated/contracted cost of rehabilitation and contractor characteristics where available, and c) village (corresponding to the tank location) level characteristics such as population distribution along ethnic lines, political affiliation of village leader (gram panchayat members and President), village level voting share to the party of the local Member of Legislative Assembly (MLA), village level infrastructure, and market connectivity. The data collection for the non-experimental component of the study is complete, and the data analysis is currently underway.
In the second, experimental component of the study, the researchers used a randomized trial approach, where a subset are randomly assigned to be rehabilitated in the phase 4 of rehabilitation in 2018. For this second component, we worked with the Government of Telangana to identify a sample of 92 tanks. From the sample, we randomly assigned 46 tanks to be rehabilitated in phase 4 and have followed up to ensure that most of these are treated. A few of them may not be rehabilitated because there are engineering reasons that could imply rehabilitation not be economically feasible. The rehabilitated tanks from our selected list under phase 4 form our treatment group, which we will compare with the remaining 46 tanks in our sample that serve as control and therefore will not restored during 2018.
A sample of 30 farms per tank were randomly selected among all farmers with plots in the tank’s command area (a term for the area served by a tank used by hydrologists and engineers) – in the event the number of farms were less than 30, then all farms will be sampled. These constitute our subject population. Subjects in the tank command area for the 844 tanks in our study (752 in the non-experimental component, 92 in the experimental component) were informed whether the water tank that services their farms has been taken up for repairs. In the experimental component, we explain that the order of repairs was randomly assigned, whereas in the non-experimental component, we explain that the order was based on a set of government guidelines. In both components, the subjects will be asked to answer survey questions on agriculture production on their plots in the tank command area as well as their plots elsewhere. Additionally, a village level survey will be administered to village leaders/village officials to obtain village economy level data.