The impact of agricultural extension on farm production in resettlement areas of Zimbabwe

This study contributes to the literature on the impact of farmer contact with agricultural extension services on farm productivity, drawing on a unique panel sample of households residing in three resettlement areas of rural Zimbabwe. It pays particular attention to the potential confounding effects of the biases identified by Birkhaeuser, Evenson, and Feder. Specifically, we exploit the longitudinal nature of our data to estimate the impact of extension on the value of crop production per hectare, with and without controls for unobservable household fixed effects. The attraction of this estimator is that the differencing process rids the specification of the correlation between extension and the disturbance term. We find that after controlling for innate productivity characteristics and farmers' ability using household fixed- effects estimation, access to agricultural extension services, defined as receiving one or two visits per agricultural year, raises the value of crop production by about 15%. This parameter estimate is statistically significant. Another unique feature of these data are, for a subsample, extension worker assessments of farmers' ability. We find that farmers with above-average ability are indeed more productive, producing 40%-50% higher output per hectare of cropped area. Controlling for innate productivity using locality dummies, farm plot characteristics, and farmers' ability using these assessments of ability, we continue to obtain a positive association between access to extension and productivity, an association that is equal in magnitude to our fixed-effects results. However, we also find considerable variability in these parameter estimates across individual crop years.