To select the 1,400 participants, we applied a two-stage random sampling design. In the first stage, we sampled eight villages randomly for each treatment/control group. We randomize the treatment status at the village level (not the household level) to eliminate the spillover effect of the interventions. In the second stage, we sampled 35 farm households in each village from the farmer’s registration list of the Department of Agrarian Services. Then, we sent out invitations to farmers to the training/study/placebo session, which we will hold in the village.
To assess the impact of the intervention, we will compare the treated farmers to the control farmers. As for those who do not participate in the assigned session (i.e., non-compliers), we will provide the session/coupon additionally by visiting non-participant households individually. Thus, our experiment is basically a pure randomized controlled trial and we will attempt to estimate the average treatment effect. If we have a non-negligible number of non-compliers who reject project participation (including the household survey), we also estimate the average treatment effect on the compliers to check the robustness of our estimates.
In the training/study/placebo session, the farmers will receive a printed manual on the content of the session (except the control farmers), a farm work record book to fill in the agronomic practices of paddy cultivation (an eight-page booklet worth 50LKR), as well as free tea and snacks (worth 60 LKR per person). Additionally, we will distribute an agricultural tool, worth about 900 LKR, for three farmers who we will select by lottery. In addition, when the farmers submit the farm work record book during the harvest season, they will receive 200 LKR. (These is basically compensation to the participants for the potential income they gave up by devoting their time to the project.)
In the subsidy program, we will provide four subsidy levels: 500 LKR, 1,000 LKR, 1,500 LKR, and 2,000 LKR per farmer to compensate for part of the costs of organic fertilizers used in the paddy fields. Our estimate of the minimum cost of organic fertilizers is 3000 LKR per acre. At the one-day training session, we will provide a coupon to farmers in the [T2] group, which indicates the subsidy amount assigned to the farmer. The coupon can be reissued, but is not transferable. Then, we will provide the money according to the coupon and certification by the village-level officers in the harvest season (February to March in 2020).
In the harvest season, we will also conduct a crop-cutting survey of all 1,400 farmers, for which they will receive 500 LKR for their support of and participation in the survey.