In the course of policy formulation, it is impractical to rely on unassisted intuition. Models provide a logical abstract template to sort out complicated chains of cause and effect, and influence between the numerous interacting variables in an economy. By virtue of their logically consistent framework, they can provide the analyst and policymaker with a valuable economic representation of the sector and a laboratory for testing ideas and policy proposals (Hazel and Norton, 1986:2). Though imperfect abstractions, economists can experiment, at least logically, the effect of alternative policy options. Models have become a useful devise for formulating plans and investigating trade-offs. They are used mainly for forecasting, consistency checks and optimisation. It must be emphasized that while models provide a formal and quantified framework that is an irreplaceable adjunct to the processes of policy thought, they are not substitutes for the exercise of reasoning, judgement and political choice.
More than sixty years of experimentation, since Jan Tinbergen formulated the first structural macroeconomic model for the Dutch economy in 1936, has brought considerable progress in the field. Macroeconomic models have undergone a lot of refinement in line with the changing economic paradigm, new research on economic theory, development of new algorithms to solve large non-linear systems of equations, and advances in computer hardware and software, which have led to richer and more complex models. A wide spectrum of choice is now available, ranging from sectoral to economy-wide models, static to dynamic and short to long term incorporating insights of many theoretical approaches including Keynesian, neoclassical, monetarist, supply-side, and rational expectations.