Relative price adjustment and the UK Philips curve

We find that measures of the distribution of relative price changes are significant when included in a standard model of the UK Phillips curve based on time dependent price adjustment. Since the inclusion of these variables is not implied by this model but is implied by a state-dependent model of price adjustment or by a time-dependent model with allowance for heterogeneity among price-setters, we conclude that the familiar time-dependent model does not provide a complete account of the Phillips curve.