Data Adjustments for Model Development
Model development began with the identification of enterprise budgets that were consistent with those found in each of the regions (PCU, 2002), Table 2). For example sorghum/millet/cowpea enterprise budgets were included in the North West and North East regional models, but not in the models of the North Central, South East, South South and South West.
The resulting regional enterprise budgets had to be adjusted to reflect regional differences. For example, enterprise budget labour costs were adjusted by an index of regional labour costs. We calculated these latter indices. Data on published labour rates for different agricultural activities for each state (PCU, 2002), Table 22) were averaged for each region and then expressed as an index of the calculated national average labour cost.
Enterprise budget crop yields and selling price were replaced by the calculated regional crop yields and selling prices. Regional crop yields were calculated from data obtained while visiting PCU. Regional prices were calculated from data provided by IITAs Rural Sector Enhancement Programme (RUSEP). The above-mentioned formed the core technical and objective coefficients for the regional models.
Regional land constraints were determined as the average of land normally devoted to the crops in the regional models. The regional land constraint was calculated from the data used to calculate regional crop yields. Regional producer food consumption was calculated from multiplying estimates of the percentage of farm production consumed on the farm (RTEP, 1995) by the regional estimate of regional production.