<xref ref-type="bibr" rid="b25">Shimer (2005)</xref> pointed out that although we have a satisfactory theory of why some workers are unemployed at any given time, we don't know why the number of unemployed workers varies so much over time. The basic Mortensen--Pissarides model does not generate nearly enough volatility in...

In the theory of competitive markets, agents act as if they do not affect prices. By analogy with the language of econometrics, agents may be said to take prices as "exogenously given," which suggests that prices are econometrically exogenous in individual behavioral equations. This involves...