The Mortensen-Pissarides model is an attractive model because it is tractable, delivers some intuitive comparative statics and permits policy analysis. However, Shimer (2005) shows that the model generates far too little volatility in its key variables - unemployment and vacancies - relative to...

Standard matching models of unemployment assume that workers and job flows are identical. This is in stark contrast to empirical evidence that job flows in fact only account for a fraction of worker ßows, that unemployment exits only account for a fraction of hires and that these fractions vary...