ABSTRACT
This study examines the concept of party system institutionalization, which serves as a key indicator for understanding the quality of modern democracies and has become a prominent topic within the party system literature, through the case of Türkiye. The literature generally assumes that highly institutionalized party systems strengthen democratic stability, whereas weak institutionalization produces adverse outcomes. However, no universally accepted method exists for assessing the institutionalization of party systems. Accordingly, this research aims to analyze the level of institutionalization in the Turkish party system between 1983 and 2015 based on electoral volatility as an indicator. The study focuses on elections held under the parliamentary system after the 1980 military coup and applies a disaggregated measure of electoral volatility, distinguishing between within-system and extra-system volatility, as well as other subcategories capturing different forms of electoral change, which allows for a clearer understanding of the nature of volatility. The findings reveal that the institutionalization of the Turkish party system increased after 2002, with most volatility occurring among actors within the system. The entry of extra-system actors has remained limited. The study provides an empirical contribution to the literature on party system institutionalization in Türkiye.
