Fall 2017 JPI

institutional factors impacting the effective number of parties by including the measurement to test
the impact of legislative electoral institutions (log(District Magnitude)) and two facets of the presidential
elections—Proximity of Presidential and Legislative Elections and the interaction term of Proximity and the
Effective Number of Presidential Candidates. Model 2 focuses strictly on the effects of ethnopolitical
cleavages by incorporating the two specifications of Ethnopolitical Group Fragmentation and Ethnopolitical
Group Concentration, in addition to their interactive effects given by Ethnopolitical Group Fragmentation X
Ethnopolitical Group Concentration. Model 3 is an additive socio-institutional model in which I incorporate
all six of the variables and interaction terms just specified. Model 4 is an interactive socio-institutional
model which MSG refer to as "fully specified" as cognizant of all the possible factors and interactions
that we are studying. 30 However, as mentioned above, GBC take issue with this notion. Model 4 has
five of the six variables included in Model 3 but instead of using the interaction term between
Ethnopolitical Group Fragmentation and Ethnopolitical Group Concentration, it uses an interaction term
representing a combination of both the institutional and sociological factors by taking the product of
log(District Magnitude), Ethnopolitical Group Fragmentation, and Ethnopolitical Group Concentration.
RESULTS
My results with the newer data are detailed in Tables 1 and 2, where Table 1 shows the results
for determinants of the effective number of electoral parties using our four models, whereas Table 2
shows the results for those models with respect to the effective number of legislative parties. The
strictly institutional model (Model 1) accounts for 34% of the variation in our Electoral Parties variable
and 42% of the variation in the number of legislative parties. The strictly sociological model (Model
2) accounts for 27% of the variance in the number of electoral parties (a decrease of 7% from the
institutional model), and 17% of the variation in the number of legislative parties (a decrease of 25%
from the institutional model). The additive effects of electoral institutions and ethnopolitical cleavages
in Model 3 account for 46% of the variation in number of electoral parties and 52% of the variation
in number of legislative parties. This is an increase compared to the institutional model of 12% in the
electoral party system and 10% in the legislative system. Finally, the interactive socio-institutional
model (Model 4) has the most explanatory power out of all the models and accounts for 65% of the
variation in the number of electoral parties and 65% in the number of legislative parties.
My results are consistent with MSG’s in proving the significant effect of the Proximity of
Presidential and Legislative Elections on the number of parties. For both electoral and legislative parties,
my results are significantly negative across all four models. This verifies that when the presidential and
legislative elections are maximally proximate (concurrent), this significantly reduces the number of
parties in the system as preferences are aggregated similarly when both branches are voted in at the
same time.
However, these results contain some key differences from MSG’s results with respect to the
ethnopolitical cleavages. Firstly, while the additive and interactive models are more explanatory of
both party systems like MSG’s results, contrary to their results in this case the sociological model
(Model 2) had much less explanatory power than the strictly institutional model (Model 1). Moreover,
in both tables, the Ethnopolitical Fragmentation variable is not a significant indicator in contrast to MSG’s
results. Unlike the ELF, PREG, and Alesina et al. measurement, MSG’s calculations include
ethnopolitical concentration as part of the formula for their fragmentation variable, while Alesina’s
methods focus solely on social cleavages such as language and religion. However, as MSG point out,
30 Mozaffar, Scarritt, and Galaich, Electoral Institutions, 385.
JPI Fall 2017, pg. 57