Party Institutionalization

Understood as “the process by which parties form consistent patterns of mass mobilization and internal organization”, party institutionalization is calculated using two different indicators: namely, the average party age and the index of party stability (IPS). While the former looks at the average age of the parties obtaining at least 10 % of the votes in a certain legislative election, the latter “weights and rewards the electoral achievement of parties in a sequence of elections” through the progressive enhancement of the proportion of the total vote for political parties in a given election over time (see Lewis, 2006; Casal Bértoa, 2012: 456-458).


Please cite the following database as: Casal Bértoa, F. (2016): Database on WHO GOVERNS in Europe and beyond, PSGo. Available at: