It is widely believed that economic inequality significantly affects political inequality, and vice versa. However, there has been a lack of empirical evidence about this relationship, particularly, in cross-national comparative research. This is largely because cross-national measures of political inequality are underdeveloped. To fill this gap, this study introduces a new way of conceptualizing and measuring political inequality and constructs the Political Inequality Index (PII), which is mainly based on objective indicators. Additionally, the Political Power Inequality Index (PPII) based on subjective indicators is presented as an alternative measure. This research then explores the features of these measures and investigates the impact of economic inequality on political inequality with the measures. The dynamic panel data analysis controlling for endogeneity provides little evidence that income inequality has a significant effect on political inequality, however.

人们普遍认为，经济不平等会严重影响政治不平等，反之亦然。但是，缺乏关于这种关系的经验证据，尤其是在跨国比较研究中。这主要是因为对政治不平等的跨国衡量标准不完善。为了填补这一空白，本研究引入了一种新的概念化和衡量政治不平等的方法，并构建了主要基于客观指标的政治不平等指数（PII）。此外，政治权力不平等指数（PPII）是基于主观指标的一种替代措施。然后，本研究探索了这些措施的特征，并通过这些措施研究了经济不平等对政治不平等的影响。控制内生性的动态面板数据分析几乎没有证据表明收入不平等对政治不平等有重大影响。