Reassessing the Relationship between Billionaires, Billionaires’ Wealth and Per-Capita GDP : A Gini Regression Analysis

In this paper, Gini Regression Analysis (Olkin and Yitzhaki 1992) is applied to check the robustness of the positive correlation of the number of billionaires, billionaires' wealth, and the GDP per-capita, as reported in Prinz (2016). Although Gini Regression Analysis (GRA) as a method exists since more than a decade, its value for robustness checks seems not well understood. In contrast to OLS estimations, GRA is based on Gini's mean difference instead of the standard deviation. Furthermore, the method of Yitzhaki and Schechtman (2012) that is also based on GRA, is applied in this paper to test the monotonicity of the relationship between the independent billionaire variables and GDP per-capita. The result is that although the positive correlation of the number and wealth of billionaires with GDP per-capita is robust for the complete sample of countries, this cannot be sustained when countries are separated into poor and rich ones