Economists don't know what they're talking about.
In the current economic crisis one major school of economists, the Keynesians, propose massive government spending to stimulate the economy while another major school of economics, the Austrian School, warns that this will inevitably trigger high inflation and should be avoided at all costs. Both schools of thought have an impressive amount of Nobel laureates backing up their respective views, and are well respected for their views and models of the world. So should the government spend massively to regain its footing? Nobody knows.
In an economic stagmire such as the one we are experiencing now economists look back at similar scenarios of the past to get an idea of how to move forward . What triggered the great depression that started in 1929 and didn't end until the second world war? The keynesians believe that underconsumption and overinvestment caused it. The Austrian school of economics believe it was caused by the fall of money supply. Or as the Wikipedia article on the causes of the great depression states: "historians lack consensus in describing the causal relationship between various events and the role of government economic policy in causing the Depression." In other words: Nobody knows.
What about housing prices? Since they are at the heart of the crisis there's a keen interest in knowing whether they have reached the bottom or are still sliding. New numbers have just come out telling us that U.S. house prices rose 0.9% from April to May on a seasonally adjusted basis. Most experts had expected them to fall by 0,2%. Is this a green shot that will soon turn brown, or is it the start of a recovery? Nobody knows.
These examples are in no way unique. The June edition of the 1993 OECD Economic Outlook may have the best example of just how useless our macroeconomic models really are. The official GDP growth and inflation forecasts of the G7 countries from 1987 -92 were compared with a model that simply predicted that next year will be the exact same as this year. And they were equally good. The inflation forecast was even a little bit better. In other words, guessing that next years inflation will be the same as this years is a good a guess as the one government econmists spend vast resources deriving from complicated models. And these forecasts are the ones we base our econnomic policy on. And they're random. Nobody knows.
Why are we still using these models? Probably a combination of several reasons. Tradition is one. These models and their assumptions are the ones we have always used. Career economics is another. It is not unknown in science that the practitioners tend to stick to their models, since they have been using them for all of their careers. Old habits die hard, and it's hard to teach an old dog new tricks. Thirdly it's a question of mathematics. Most models assume that all human beings act in a rational way which anyone can tell you is not true. As a matter of fact a famous study has shown that the only two groups of people that act as economically rational beings are economists and psychopaths. Most models also assume that people don't interact. And that they all have perfect information about the market. Which is obviously not true. But these things are hard to model mathematically, so most economists just stick to their guns. The famous physicist Max Planck once remarked that in early life he had thought of studying economics, but had found it too difficult.
Where do we go? The problems of classical economics run deep. Macroeconomists can't agree on the most fundamental of things, give random predictions and advice, and base their models on assumptions that bear no resemblance to real life scenarios. It's not just the little things that don't work, it's the whole thing. What is needed is a fundamentally new way of thinking. People aren't rational. They don't have perfect information about the market. Supply doesn't always follow demand. We need a whole new framework. Behavioral economics, which Vernon L. Smith and Daniel Kahneman won the nobel prize for studying might be one way. Complexity and Chaos theory might be another.
Will we ever fully understand macro economy?
I don't know, but I do know one thing.
Right now the emperor has no clothes on.