8The possibility that households do not immediately perceive aggregate shocks is lent credibility by recent work of Aruoba (2008), who shows that advance and preliminary releases of national income accounts data are not unbiased predictors of the final revised data. If even the U.S. national statistical agency is not able to construct an unbiased estimate of the truth immediately, it seems hard to argue against the plausibility of the proposition that households are even slower on the uptake.