The Long Short Run
Japan since the start of the 1990’s provides strong evidence that what economists call "the short run" can last for decades, and then be followed not by a return to the old normal, but by a transition to a new normal in which economic depression casts a long shadow. What we have seen since 2008 is that Japan is not an exception.
BERKELEY – Before 2008, I taught my students that the United States was a flexible economy. It had employers who were willing to gamble and hire when they saw unemployed workers who would be productive; and it had workers who were willing to move to opportunity, or to try something new in order to get a job. As bosses and entrepreneurial workers took a chance, supply would create its own demand.
Yes, I used to say, adverse shocks to spending could indeed create mass unemployment and idle capacity, but their effects would be limited to one, two, or at most three years. And each year after the initial downturn had ended, the US economy would recover roughly 40% of the ground between its current situation and its full employment potential.
The domain of the Keynesian (and monetarist) short run, I said, was 0-2 years. When analyzing events at a horizon of 3-7 years, one could safely assume a “classical” model: the economy would return to full employment, while changes in policy and in the economic environment would alter the distribution but not the level of spending, production, and employment. Beyond seven years was the domain of economic growth and economic institutions.