This study aims to research the effects of unemployment wages current account and consumer price index (CPI) on the real gross domestic product (RGDP), which, in the optimum currency area (OCA) theory, supposes that countries with higher factor mobility can significantly profit from the currency area. However, in this study, it is shown that the considered optimum currency crisis (OCC) model is affected by mobility factors, as the defined theory has not been perfectly realised in the Eurozone.Design/methodology/approach: In this study, Breusch–Pagan–Godfrey and Lagrange multiplier (LM) tests are used for supporting the survey for better estimation of the panel cointegration tests, where Pedroni's (1995, 1997) technique is used. The unit root tests are employed, of which the Phillip–Perron and augmented Dickey–Fuller tests (unit root test, Dickey, D. and W. Fuller, 1979) are considered.Findings: It can be concluded that demand shocks will tend to be more asymmetric instead of being symmetric, even though they are in the customs union (CU). However, Polish workers in a given scenario may move to Germany, but because of the rigidity of the labour market and qualification differences between workers, the interregional integration of member countries is reduced, and this reduces the absorption of asymmetric shocks. In Germany, where strong employment protection and rigidity are observed in comparison to Poland, although there has been historical migration and economical collaboration, unfortunately, the integration of the two countries’ economies has not been realised.Research limitations/implications: Quantitative research on fiscal union and the estimation of its effects is not possible because there is no practical experience of fiscal union throughout the European Union (EU). However, quantitative research is used for estimating the effects of OCA in the Eurozone. Quantitative investigation is particularly focused on the monetary union and single currency and its impact on growth rate. In this study, the ordinary least squares (OLS) method and panel cointegration test are employed for estimating the effects of the considered variables.Practical implications: The Eurozone and the application of a single currency throughout the EU was a considerably difficult task. In addition, the adoption of a single currency was not easy for those member countries that fulfilled the “convergence criteria” (or “Maastricht criteria”) and who joined the Eurozone, because only adoption is not enough; maintenance of those criteria is also required. This study analysed the application of the Eurozone in the light of the OCA of Mundel's theory.Social implications: The OCA is important for member countries’ economic relations. However, the application of a single currency is not easy and needs to be controlled and regulated to ensure best practises throughout the Eurozone. Monetary integration is not a simple process, and Eurozone countries’ financial difficulties affect each other’s markets’ indifferent aspects. Particularly in any market recession, demand shocks tend to have different effects. Furthermore, in comparison to the monetary union, the CU has a considerable impact on trade enlargement.Originality/value: In this study, the effects of the independent variables “wages, unemployment, CPI and capital flow” on the dependent variable “RGDP” is considered, which, in the OCA theory, supposes that countries with higher factor mobility can significantly profit from the currency area. In application, it was turned into crisis because of inadequate monetary and fiscal application. In this paper OCA is questioned in the light of the Eurozone for bringing better understanding to these difficulties. The considered model and estimations are used for evaluating to create sustainable monetary integration for economic growth
