在本文中，上述問題都將被考量在內，本文利用30個國家在1985年至2010年間的非平衡長期縱橫資料(unbalance panel data)，以高所得者所得份額(Top x % Income Share)取代吉尼係數來衡量所得不均度，並利用兩階段最小平方法來解決模型存在的內生性問題。
本文的實證結果顯示，進出口占GDP之比重、出口占GDP之比重、對內外人直接投資占GDP之比重對所得不均度有負向顯著的效果。若將國家分成開發中和已開發國家，已開發國家實證結果仍然顯示全球化會對所得不均會產生負向的影響，但在開發中國家的估計結果則不顯著。最後，以高所得群體內部的所得不均度來看也有相同的結論，結果顯示，全球化也會使高所得群體內部的所得不均度下降。;For a long time economists have been working on the effects of globalization on income inequality. There are two shortcomings in past literature. First, most of these literature use Gini coefficient to measure income inequality. Due to the household surveys is not accurate income statistics and lack the income information of high-income, Gini coefficient can’t accurately measure income inequality in the country. Second, literature don’t control the endogeneity in the models.
In this paper, these shortcomings are addressed. We use unbalance panel data of 30 countries from 1985 to 2010. We employ Top x % income share to measure income inequality rather than Gini coefficient. Additionally, we use two stage least squares approach to control the endogeneity in the model.
Our empirical results show that the import plus export to GDP ratio, the export to GDP ratio and the inward foreign direct investment to GDP ratio have a negative significant effect on income inequality. If we divide countries into developing and developed countries, the empirical results of developed countries still show that the globalization have a negative effect on income inequality. However, we find no robust effect of globalization on income inequality in developing country. Furthermore, a similar results holds for top income inequality: globalization would lead to lower level of top income inequality.