29 November 2018In this paper we extend the usual Lucas supply curve to allow the likely external influence on inflation, together with domestic conditions. We test the relationship between the inflation surprise, the output gap and the real exchange rate using simple time series regressions on annual data for a list of 16 developed countries. These tests confirm the empirical relevance of the Lucas supply curve but also support the assumption that part of the inflation surprise may come from unexpected variations of the real exchange rate.