Which Countrie's Income Gap is about Decrease? New Evidences from Panel unit Root Tests with Multiple Endogenous Structural Breaks

In this paper, we analyze the dynamics of income gap between 138 countries with USA by using time series model of convergence hypothesis and various panel unit root tests over period 1950-2008. All panel unit root tests don’t reject the null hypothesis of unit root. Univariate unit root tests results show that GDP per capita of South Korea, Switzerland, Austria, Lesoto and Hungry catch up with USA and GDP per capita of Syria, New zealand, and Jordan diverged from USA GDP per capita. The estimation shows that the breaks were clustered around specific dates, such as oil shocks or financial crises. Also,the results show that almost poor countries stay poor and almost rich countries stay rich yet. Only some countries same as South Korea, Hong Kong, Singapore, Taiwan, India, and China could escape lag deadlock and the countries e.g. Syria, Madagascar, Kenya, and Comoro moved into poverty trap. The distributions of GDP per capita in various years confirmed our results.