Neil Irwin has a piece noting housing's importance in the downturn, which gets things half right. First, housing is typically important in economic cycles, as he says, but the picture is quite different than Irwin implies. In a typical recession housing construction falls because it is very sensitive to interest rates. Most recessions are brought on by the Fed raising interest rates to slow the economy. In these cases the decline in housing is a deliberate outcome of Fed policy, not an accidental outcome to be avoided. In contrast, the most recent downturn was brought on by a collapse of a housing bubble. This made it qualitatively different from most prior downturns (the 2001 recession was also bubble induced) in several different ways. First, construction was proceeding at an extraordinary rate of more than 6.0 percent of GDP before the collapse, compared to an average rate of just over 4.0 percent of GDP. This meant that housing contracted far more than it would in a typical downturn. Furthermore, because of the overbuilding of the bubble years, housing fell further than normal, hitting levels just above 2.0 percent of GDP. And, because the downturn was not brought on by a rise of interest rates it could not be reversed by a drop in interest rates.Read rest here.