Is the Phillips curve flat across the whole distribution of inflation? Evidence from the EU and the USA

The aim of this thesis is to investigate a possible flattening of the Phillips curve across different quantiles of the distribution of inflation. By using a quantile regression framework with different Phillips curve models that are widely used in the literature, it is uncovered that the so-called flattening of the Phillips curve can mainly exist for low and medium inflation levels. What is found is that the flattening is more intense in the United States compared to the European Union and that the Phillips curve cannot be considered as a reliable monetary policy tool in the former, while in the latter, there seems to be still credibility in the Phillips curve relationship.