An obstacle for the euro zone: How to identify the origin of the growing heterogeneity between the countries?

The growing heterogeneity and divergence of income levels between the euro-zone countries threatens the long-term existence of the euro zone. But one important obstacle lies in identifying the origin of this growing heterogeneity between the euro-zone countries. Does it result from the use of comparative advantages and productive specialisation made possible by the elimination of currency risk, as is normal in a currency area? If this is the case, then a normal response would be to introduce solidarity policies to correct this heterogeneity; Does it result from some countries not implementing the right economic policies or the necessary reforms? If this is the case, then these countries should be required to implement said reforms and there would be no reason to introduce solidarity mechanisms. At p resent, the southern euro-zone countries put forward the first type of explanation for the heterogeneity (divergent productive specialisations between the countries, which is normal in a currency area); the “frugal” countries put forward the second type of explanation (lack of reform). It is likely that both types of explanations are right .