Farm level impact assessment of Bt corn in the Philippines using propensity score matching techniques
2012
Tobias, A.M., International Rice Research Inst., DAPO box 7777, Metro Manila (Philippines). Social Sciences Div.
The farm level impact assessment of Bt corn in the Philippines was examined using propensity score matching (PSM). The effect of using Bt corn was determined through the average treatment effect on the treated (ATT) while controlling for selection bias. Primary data were collected from 468 corn farmers in two corn-growing areas in the country: Isabela and South Cotabato. Several analytical tools were employed in this study: Counterfactural Evaluation Method, Propensity Score Matching, Logit Analysis, Cost and Returns Analysis, Endogeneity Test and the Two-Stage Least Squares (2 SLS) method. The ATT was estimated by Nearest Neighbor Matching (NNM) method. Results of the NNM showed that Bt corn adoption caused a positive and significant effect on net income. NNM causal effects of adoption on increase in yield suggest that yield of Bt corn, are higher by 4,794.15 kg per hectare than non-Bt corn, net income is around Php 25,069.33 per hectare while pesticide cost of adopters are around PhP123.41 per hectare. Results of the endogeneity test showed that varietal adoption is endogenous to yield. The farm level impact of Bt corn adoption indicated that Bt corn variety, amount of fertilizer applied and location are significant variables that affect corn yield. Using Bt corn will result to a yield increase of about by 1.18 metric tons per hectare.
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