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The Effects of Agricultural Extension on Farm Yields in Kenya

  • Robert E. Evenson


    (Economic Growth Center, Yale University)

  • Germano Mwabu
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    The paper examines effects of agricultural extension on crop yields in Kenya controlling for other determinants of yields, notably the schooling of farmers and agro-ecological characteristics of arable land. The data we use were collected by the Government of Kenya in 1982 and 1990, but the estimation results reported in the paper are based primarily on the 1982 data set. The sample used for estimation contains information about crop production, agricultural extension workers (exogenously supplied to farms), educational attainment of farmers, usage of farm inputs, among others. A quantile regression technique was used to investigate productivity effects of agricultural extension and other farm inputs over the entire conditional distribution of farm yield residuals. We find that productivity effect of agricultural extension is highest at the extreme ends of distribution of yield residuals. Complementarity of unobserved farmer ability with extension service at higher yield residuals and the diminishing returns to the extension input, which are uncompensated for by ability at the lower tail of the distribution, are hypothesized to account for this U-shaped pattern of the productivity effect of extension across yield quantiles. This finding suggests that for a given level of extension input, unobserved factors such as farm management abilities affect crop yields differently. Effects of schooling on farm yields are positive but statistically insignificant. Other determinants of farm yields that we analyze include labour input, farmer experience, agro-ecological characteristics of farms, fallow acreage, and types of crops grown.

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    Paper provided by Economic Growth Center, Yale University in its series Working Papers with number 798.

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    Length: 22 pages
    Date of creation: Sep 1998
    Date of revision:
    Handle: RePEc:egc:wpaper:798
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    1. Koenker, Roger & Bassett, Gilbert, Jr, 1982. "Robust Tests for Heteroscedasticity Based on Regression Quantiles," Econometrica, Econometric Society, vol. 50(1), pages 43-61, January.
    2. Anderson, Jock R. & Feder, Gershon, 2007. "Agricultural Extension," Handbook of Agricultural Economics, Elsevier.
    3. Schultz, Theodore W, 1975. "The Value of the Ability to Deal with Disequilibria," Journal of Economic Literature, American Economic Association, vol. 13(3), pages 827-46, September.
    4. Koenker, Roger W & Bassett, Gilbert, Jr, 1978. "Regression Quantiles," Econometrica, Econometric Society, vol. 46(1), pages 33-50, January.
    5. Birkhaeuser, D. & Everson, R. & Feder, G., 1989. "The Economic Impact Of Agriculture Extension: A Review," Papers 567, Yale - Economic Growth Center.
    6. Moshe Buchinsky, 1998. "Recent Advances in Quantile Regression Models: A Practical Guideline for Empirical Research," Journal of Human Resources, University of Wisconsin Press, vol. 33(1), pages 88-126.
    7. Feder, Gershon & Slade, Roger H, 1986. "The Impact of Agricultural Extension: The Training and Visit System in India," World Bank Research Observer, World Bank Group, vol. 1(2), pages 139-61, July.
    8. Simon Appleton & Arsene Balihuta, 1996. "Education and agricultural productivity: Evidence from Uganda," Journal of International Development, John Wiley & Sons, Ltd., vol. 8(3), pages 415-444.
    9. T. Paul Schultz & Germano Mwabu, 1997. "Labor Unions and the Distribution of Wages and Employment in South Africa," Working Papers 776, Economic Growth Center, Yale University.
    10. Bindlish, V. & Evenson, R., 1993. "Evaluation of the Performance of T&V Extension in Kenya," Papers 208, World Bank - Technical Papers.
    11. Umali-Deininger, Dina, 1997. "Public and Private Agricultural Extension: Partners or Rivals?," World Bank Research Observer, World Bank Group, vol. 12(2), pages 203-24, August.
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