Political fragmentation is the fragmentation of the political landscape into different parties and groups, which makes it difficult to deliver effective governance.[1] Political fragmentation can apply to political parties, political groups or other political organisations.

Measures of political fragmentation

One aspect of political fragmentation can be measured by effective number of parties.[2]

Effects of political fragmentation

Scholars, journalists and politicians have theorized about a number of potential effects of political fragmentation. For example, it has been argued that higher fragmentation allows voters to better represent their political spectrum of political positions. The length of government coalition formation has also been argued to increase with number of parties and decreases with preexisting political groups.[3] The strength of these effects has been hypothesized to depend on whether it is the government or the opposition that are fragmented.[4] However, the political fragmentation of parliaments has little causal effect on a number of dimensions of the quality of democracy.[5]

The veto player theory predicts that higher fragmentation relates to gridlock,[6] while other literature does not observe increased gridlock.[7]

Prediction of political fragmentation

The political fragmentation, represented by effective number of parties, is roughly estimated with the seat product model,[8][9] and increases with district magnitude and assembly size. The Duverger's law predicts majoritarian elections with district magnitude of one favor a two-party system and proportional representation increases the number of parties. In proportional representation, higher electoral thresholds reduce number of parties represented while increasing wasted vote. Fragmentation tends to moves toward an equilibrium, regardless of the type of voting system.[10]


  1. ^ Pildes, Richard H. (2019). "The Age of Political Fragmentation".
  2. ^ "Election indices dataset, Gallagher, Michael, 2021".
  3. ^ Ecker, Alejandro; Meyer, Thomas M. (2020). "Coalition Bargaining Duration in Multiparty Democracies". British Journal of Political Science. 50: 261–280. doi:10.1017/S0007123417000539. S2CID 158378332.
  4. ^ Meka, Eltion (2022). "How much opposition? Political fragmentation and changes in democracy". Contemporary Politics. 28 (5): 517–538. doi:10.1080/13569775.2021.2015086. S2CID 245459910.
  5. ^ Valentim, Vicente; Dinas, Elias (2024). "Does Party-System Fragmentation Affect the Quality of Democracy?". British Journal of Political Science. 54: 152–178. doi:10.1017/S0007123423000157. S2CID 236793765.
  6. ^ Tsebelis, G. (15 September 2002). Veto Players: How Political Institutions Work. Princeton University Press. ISBN 9780691099897.
  7. ^ McGann, Anthony J.; Latner, Michael (2013). "The Calculus of Consensus Democracy". Comparative Political Studies. 46 (7): 823–850. doi:10.1177/0010414012463883. S2CID 154367801.
  8. ^ Taagepera, Rein (2007). "Predicting Party Sizes". Oxford University Press
  9. ^ Li, Yuhui; Shugart, Matthew S. (2016). "The Seat Product Model of the effective number of parties: A case for applied political science". Electoral Studies. 41: 23–34. doi:10.1016/j.electstud.2015.10.011.
  10. ^ Coleman, Stephen (1995). "Dynamics in the fragmentation of political party systems". Quality & Quantity. 29 (2): 141–155. doi:10.1007/BF01101895. S2CID 153425524.