Abstract
This paper investigates impact heterogeneity in the adoption of improved maize varieties using data from rural Tanzania. We used a generalized propensity-score matching methodology, complemented with a parametric econometric method to check the robustness of results. We found a consistent result across models, indicating that adoption increased food security, and that the impact of adoption varied with the level of adoption. On average, an increase of one acre in the area allocated to improved maize varieties reduced the probabilities of chronic and transitory food insecurity from between 0.7 and 1.2 % and between 1.1 and 1.7 %, respectively. Policies that increase maize productivity and ease farmers’ adoption constraints can ensure the allocation of more land to improved technologies and, in doing so, enhance the food security of households.
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Notes
We thank the anonymous referee for suggesting this analysis.
It should be kept in mind that the GPS score methods are designed for analyzing the effect of a treatment level, therefore they specifically refer to the subpopulation of treated units/adopters. This implies that including untreated units might lead to misleading results (Guardabascio and Ventura 2013). Accordingly, in the GSP and dose–response estimation we only considered positive observations.
Though variables explaining the potential endogenous variables such as the use of fertilizer and other crop improved varieties are included in the regression models, we estimated the models including and excluding these potential endogenous regressors; however, we only report results including potential endogenous variables to save space and because the food security impact results are numerically close. The average marginal effects were −2.7 %, −1.2 %, −1.1 %, 1.5 % and 0.9 % for chronic food insecurity, transitory food insecurity, breakeven, and food-surplus in food security, respectively. The average marginal effect for per capita food consumption was 14,701 TSH.
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Acknowledgement
This study is supported by the Australian Centre for International Agricultural Research (ACIAR) and the Australian International Food Security Research Centre (AIFSRC) through the International Maize and Wheat Improvement Center (CIMMYT)-led Sustainable Intensification of Maize-Legume Cropping Systems in Eastern and Southern Africa (SIMLESA) program, and Adoption Pathways Project. The views expressed here are those of the authors and do not necessarily reflect the views of the donor or the authors’ institution. The usual disclaimer applies. We would also like to thank the anonymous reviewer and the chief editor of this journal for their valuable comments and suggestions which improved the quality of the paper.
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Kassie, M., Jaleta, M. & Mattei, A. Evaluating the impact of improved maize varieties on food security in Rural Tanzania: Evidence from a continuous treatment approach. Food Sec. 6, 217–230 (2014). https://doi.org/10.1007/s12571-014-0332-x
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DOI: https://doi.org/10.1007/s12571-014-0332-x