Dual labour markets and nominal rigidity

The conventional menu cost framework performs poorly with realisticlabour supply elasticities: the menu costs required for pricerigidity are very high and the welfare consequences of monetarydisturbances are negligible. We show that the presence of duallabour markets greatly improves the performance of the frameworkboth by reducing the minimum effective menu costs and by boostingthe welfare consequences. In addition, the introduction of duallabour markets provides an explanation of procyclical productivityand the shrinking of wage differentials during booms, in linewith stylized facts on business cycles.