Does Party-System Fragmentation Affect the Quality of Democracy?

47 Pages Posted: 12 Mar 2020 Last revised: 28 Apr 2021

See all articles by Vicente Valentim

Vicente Valentim

University of Oxford - Nuffield College

Elias Dinas

University of Oxford

Date Written: February 13, 2020


Given their central role in the process of decision making, party-systems are usually expected to affect a number of democratic outcomes. Research on this topic, however, has suffered from problems of endogeneity stemming from the fact that the characteristics of the party system are endogenous to many other dynamics in a polity. We overcome this issue by putting forward an instrument for the number of parties in a system, based on the level of fragmentation added by parties that narrowly make it to parliament. We then test the effect of party-system fragmentation on the quality of democracy, drawing upon a large battery of outcomes. Running against previous literature, we find that a higher number of parties leads to more fractionalized governments, but it has no impact on other democratic outcomes. The null effect persists after using a large number of different model specifications, operationalizations of the treatment variable and subsamples. Our results cast doubt on the normative implications of party-system fragmentation.

Keywords: party systems, quality of democracy, null findings, instrumental variables, causal inference

Suggested Citation

Valentim, Vicente and Dinas, Elias, Does Party-System Fragmentation Affect the Quality of Democracy? (February 13, 2020). Available at SSRN: or

Vicente Valentim (Contact Author)

University of Oxford - Nuffield College ( email )

United Kingdom

Elias Dinas

University of Oxford ( email )

Mansfield Road
Oxford, Oxfordshire OX1 4AU
United Kingdom

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Abstract Views
PlumX Metrics