...It is hard for non-economists to understand how peculiar the predominant macroeconomic models were. Many assumed demand had to equal supply – and that meant there could be no unemployment. (Right now a lot of people are just enjoying an extra dose of leisure; why they are unhappy is a matter for psychiatry, not economics.) Many used “representative agent models” – all individuals were assumed to be identical, and this meant there could be no meaningful financial markets (who would be lending money to whom?). Information asymmetries, the cornerstone of modern economics, also had no place: they could arise only if individuals suffered from acute schizophrenia, an assumption incompatible with another of the favoured assumptions, full rationality.
Bad models lead to bad policy: central banks, for instance, focused on the small economic inefficiencies arising from inflation, to the exclusion of the far, far greater inefficiencies arising from dysfunctional financial markets and asset price bubbles. After all, their models said that financial markets were always efficient. Remarkably, standard macroeconomic models did not even incorporate adequate analyses of banks. No wonder former Federal Reserve chairman Alan Greenspan, in his famous mea culpa, could express his surprise that banks did not do a better job at risk management. The real surprise was his surprise: even a cursory look at the perverse incentives confronting banks and their managers would have predicted short-sighted behaviour with excessive risk-taking....
...Fortunately, while much of the mainstream focused on these flawed models, numerous researchers were engaged in developing alternative approaches. Economic theory had already shown that many of the central conclusions of the standard model were not robust – that is, small changes in assumptions led to large changes in conclusions. Even small information asymmetries, or imperfections in risk markets, meant that markets were not efficient. Celebrated results, such as Adam Smith’s invisible hand, did not hold; the invisible hand was invisible because it was not there. Few today would argue that bank managers, in their pursuit of their self-interest, had promoted the well-being of the global economy....
...Changing paradigms is not easy. Too many have invested too much in the wrong models. Like the Ptolemaic attempts to preserve earth-centric views of the universe, there will be heroic efforts to add complexities and refinements to the standard paradigm. The resulting models will be an improvement and policies based on them may do better, but they too are likely to fail. Nothing less than a paradigm shift will do.
The full article can be found here (subscription required) or (most of it) here.
(one more reason why our 'evaluation'-mania in IB Economics is so important...)
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