A time‐series analysis of Zimbabwe's corn sales to the Grain Marketing Board

This article considers methods of cointegration testing to construct a model of Zimbabwe ‘s corn sector. Corn production, sales of corn to the government, the price of corn, and price of beef are linked together in one long‐run equilibrium (cointegrating) relation. Only the price of beef is not weakly exogenous to perturbations in this relation. That is to say, when these variables are out of long‐run equilibrium, it is through subsequent changes in the price of beef that equilibrium is restored. The other variables do not respond to a long‐run disequilibrium. Short‐run forecasts from this model are compared with expert opinion forecasts made by the government's marketing board. Possibilities for improvement in long‐run forecasting and planning are discussed.