“…This flatness is a well-known finding for many economies, whether the model estimated is a closed or open economy model -see e.g. Gali and Gertler (1999) for US, Mihailov, Rumler, and Scharler (2011) for Poland, Hungary, Slovakia, Latvia, Lithuania, Cyprus, Malta, Czech Republic, Slovenia, Bulgaria, where some estimates are even negative. Gali and Gertler (1999) argue that output gap is not proportional to real marginal cost, but real marginal cost better accounts for direct productivity gains on inflation, and so it should replace output gap in the Phillips curve.…”