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Dataset net volatility in Western Europe

Pedersen index of net volatility in legislative elections between 1950 and 2014 in Western Europe. The index was originally outlined in Pedersen, M.N. (1979) The Dynamics of European Party Systems: Changing Patterns of Electoral Volatility. European Journal of Political Research 7(1): 1-26.



Data on the least squares index of disproportionality and the effective number of parties comes from Michael Gallagher’s database or was calculated by means of Gallagher’s excel sheet.

Data on turnout rates comes from IDEA.

The Pedersen index of net volatility was calculated by means of election results. Data on election results come from Mackie & Rose (1991) and were complemented with information from the ParlGov database. Parties obtaining less than 1% of the vote share were grouped in an ‘other’ category. Decisions on what parties to consider versus parties that were the result of a split or merger of old parties were made based on election specific information as found in election reports in Electoral Studies, the European Journal of Political Research or West European Politics.

How to cite this dataset?

Dassonneville, Ruth (2015). Net Volatility in Western Europe: 1950-2014. Dataset. KU Leuven: Centre for Citizenship and Democracy.


Pedersen index dataset (CSV file)


Ce contenu a été mis à jour le 3 novembre 2016 à 13 h 24 min.