CSES Polarization Index

Description

Dalton (2008) proposes the Polarization Index, which measures ideological polarization among parties based on CSES respondents’ placement of parties on a left-right scale. It is the most widely used measure of ideological polarization and can also be used to measure ideological polarization at the mass level (see Reiljan (2020)).

Operationalization

The Polarization Index can be calculated as follows. First, the party positions are calculated as an average of the left-right scores assigned to parties by respondents, and then the polarization index is calculated using the following formula:

$$PI_k = \sqrt{ \sum_{j=1} V_{jk} (\frac{P_{jk}-\bar{P_k}}{5})^2 }$$ where $P_{jk}$ is the left-right position of party $j$ in a country-year sample $k$ and $\bar{P_k}$ is the average position of all parties considered. $V_{jk}$ is the vote share of party $P_{jk}$.

polaR

# Import Data
cses_imd <- polaR_import(source = "cses_imd",
						 path = "path/to/dataset.dta")

# Compute Measure
cses_imd <- cpi(cses_imd)

Visualization

Use cases

Publications that use this measure: