Fall 2017 JPI

data, which don’t occur here. Firstly, we can see that before MSG omitted the Effective Number of
Presidential Candidates variable, and in the corrected fully-specified models I consistently find that
Effective Number of Presidential Candidates is positive and significantly correlated with Effective Number of
Legislative Parties. This does make sense since generally more candidates indicates a likelihood of more
parties in democratic elections. 34
A key difference in Table 3 that negates one of the conclusions drawn by MSG is that while
indeed in MSG’s "fully-specified" interactive socio-institutional model, District Magnitude has a
significant negative effect on the number of legislative parties, when I add in the missing constitutive
terms detailed above, District Magnitude no longer has a significant effect. To investigate the reasons
behind this change, I also take into account that the Fragmentation X District Magnitude interaction
variable that was not included in MSG’s analysis is essential. Using my new fully-specified Model 4,
the coefficient is negative and statistically significant. However, neither the Ethnopolitical Fragmentation
variable nor log(District Magnitude) are significant by themselves in the fully-specified interactive model.
This implies that District Magnitude does not significantly affect the number of political parties when
there is no ethnopolitical fragmentation at all because presumably in that case, the preferences of the
population would be relatively uniform throughout. The coefficient of Ethnopolitical Fragmentation alone
here is irrelevant because it represents the effect of ethnopolitical fragmentation when the district
magnitude is nonexistent. Finally, the significant negative coefficient of the interaction term shows
that higher levels of ethnopolitical fragmentation will either increase the number of parties in the
system, but by a lesser margin when district magnitude is high or will limit the number of political
parties in the legislative system, conditional on a large district magnitude. As GBC point out, "district
magnitude matters in this causal story because it is the decisive factor determining electoral system
permissiveness." 35 According to MSG, ethnopolitical fragmentation tends to reduce the number of
parties overall, however ethnopolitical concentration should counteract this reductive effect.
Assuming these two things are true, that would imply that the coefficient on Fragmentation would be
negative and the coefficient on Fragmentation X Concentration be positive. However, I do not find
evidence that ethnopolitical fragmentation alone would significantly reduce the number of parties in
the system in any of the models, nor that the interaction term would be positive.
34 Kenneth Benoit "District magnitude, electoral formula, and the number of parties." 203-224.
35 Ibid, 5.
JPI Fall 2017, pg. 62