Both cycles often move in sync, but this time they aren't. So this current cycle presents the possibility to more clearly understand the differing effects of the housing construction cycle and the housing price cycle.
The large variation in both cycles across cities round the country also means that we can separate out the effect of some macroeconomic factors which are common across the country and hence shouldn't be a driver of the differences across states. In particular, interest rates have been the same across the country.