Economic stability has proven to be a very important issue in the European Union once with the international subprime crisis. There were even rumors that the Euro Area and the Union itself might disappear. Starting from the classic Macroeconomic Stabilization Pentagon, the present research compares possible measures of economic stability, bearing in mind two important aspects related to the Union – convergence and competitiveness. The purpose was to evaluate their power in signaling national economic problems. The macroeconomic stabilization pentagon together with its indicator are denotive for the stability level of a country. Important diffusion and contagion effects are to be found in the EU in terms of stability. The study makes a ranking of the efficiency of several methodological procedures used for such an assessment and points out the importance of competitiveness in insuring economic stability. This book should help professionals in European institutions construct a mix of indicators for evaluating stability. Additionally, it is an example for anyone interested in this subject, even students in Economics, International Affairs and Statistics.