Abstract
We propose a Markov switching cointegration approach to assess long run fiscal sustainability. This method allows us to simultaneously: (1) test for cointegration in the presence of significant fiscal policy changes; (2) assess the type of fiscal regime that a country experienced at a given period and (3) analyse the timing of the transition between the estimated regime types. Given its flexibility, our approach enable us to uncover a richer and more complex dynamics in the analysis of fiscal sustainability, which standard linear cointegration methods fail to capture.