We establish novel empirical regularities on firms' expectations about aggregate and
idiosyncratic components of sectoral demand using industry-level survey data for the
universe of Japanese rfims. Expectations of the idiosyncratic component of demand
differ across sectors, and they positively co-move with expectations about the aggregate
component of demand. To study the implications for in
ation, we develop a model with
firms that form expectations based on the inference of distinct shocks from a common
signal. We show that the sensitivity of in
ation to changes in demand decreases with
the volatility of idiosyncratic component of demand that proxies the degree of shock
heterogeneity. We apply principal component analysis on Japanese sectoral-level data
to estimate the degree of shock heterogeneity, and we establish that the observed
increase in shock heterogeneity plays a significant role for the reduced sensitivity of
in
ation to movements in real activity since the late 1990s