This variable has information if the country held a second election during the year of reference; otherwise it is empty. The polarization score of the election calculated from parties’ left-right placement according to expert survey data and using Dalton’s polarization index (2008). The score ranges from 0 to 10, where higher values mean higher polarization.

For more information on the methodology and some information for individual countries, please consult the methodology available at https://cise.luiss.it/cise/dataset-of-ideological-polarization-in-western-europe/