Economic Viewpoint: Economic Models and Economic Forecasting: Ptolemaic or Copernican?

Economic forecasters have come in for a lot of criticism in recent months. But this is not new. The failure to predict the boom in 1988 and ensuing inflation and balance of payments problems led to some serious re-examination of the structure of the main macroeconometric models in the UK. The speed with which the UK economy moved into sharp recession in the second half of 1990- also appeared to catch most forecasters on the hop. This Briefing Paper is not directly about forecasting; it is about macroeconometric models. However, forecasting provides by far the most extensive use of these models. Not all macroeconomic forecasters use a formal econometric model - some City economists find a spreadsheet more than adequate - but those that do find that they are an invaluable aid to clear thinking and provide an effective way of filtering all of the information that is available, in one form or another, about the economy. This paper was originally intended to provide a retrospective review of the development of UK macro-models since the late 1970s, coinciding broadly with my period at London Business School. However, it became clear that there was a need to argue more generally in favour of macro-modelling, given the numerous assaults that this activity has sustained over the last 15 years. I want to demonstrate that the conduct of research in this area - at the very least in the UK - has been, and continues to be, a progressive research strategy in the sense in which philosophers of science use this term. I believe that macro-modellers, because they have an obligation to forecast and to make the forecast public, are closer to how theoretical constructs in economics conflict with the observation of economic events, and provide a more robust testing ground for economic theories than the relatively narrow - though very important - confines of single equation statistical testing, that dominate academic journals. This should not mean that every new theoretical idea should be expected to be able to survive immediately the rigours of testing within an existing macro-model. One of the attractions of recent developments in macroeconomic theory has been an explicit attempt to seek to try to reconcile macroeconomics with micro-economic reasoning and to derive macroeconomic principles from how rational, maximizing individuals can be expected to behave in a market economy. There is always a need periodically to re-examine the basic postulates of any area of economics, especially one such as macroeconomics, which provides the basis for the conduct of national and international economic policy, and for providing explanations for economic cycles. Macro-econometric model building is a worthwhile exercise because it confronts theoretical models of how the macro-economy is supposed to work with the hard lessons of experience. The use of these models for forecasting is therefore crucial to their continued growth and development.