Political Inequality Index

Cross-national measure of political inequality based on 2 distinct dimensions: participation and representation. The 2 dimensions are aggregated by geometric averaging because each dimension is related to political inequality but clearly distinct from each other, providing neither full compensability nor full non-compensability. Consequently, using a geometric mean is an in-between solution. Then the aggregate scores are normalized with the 0-100 scale and reversed to show the level of inequality. One thing to note is that the minimum value of 0 does not mean perfect equality; likewise, the maximum value of 100 does not mean perfect inequality. They just indicate the best or worst level of performance among the observations. The PII has 2 distinctive advantages compared to other measures of political inequality: first, it overcomes a narrow version of political inequality measure such as voting by encompassing representation as well as electoral and non-electoral participation; second, it provides the best available cross-national and over-time data source for political inequality, covering 69 countries including 30 established democracies over the period between 1990 and 2016, as of 2018. The PII allows us to answer the question of to what extent citizens are treated as political equals that have equal voice to influence politics. Securing an equal opportunity or an equal starting point by encouraging political participation and making a more representative political system is crucial for a more democratic and egalitarian society.