* : significant at .05 level
To assess more precisely the impact of dominance on turnout, this impact has to be
controlled by other variables. Unfortunately, until 1981, no control variable is available,
except the number of registered voters by constituency. This variable has no impact on
turnout neither in the first round nor in the second round. Regression analysis however
reinforces the correlation analysis since dominance is systematically a significant variable of
the regression in the second round (and never in the first round). From 1988, the impact of
electoral dominance can be controlled by census data. Besides the number of registered voters
in each constituency, six variables have been chosen in accordance with classical explanations
of turnout: the percentage of the population between 18 and 25 years old, the percentage over
65 years old, the percentage of farmers, the percentages of manual workers, the percentage of
population living in rural areas, the percentage of foreigners over 18 years old in the
population of the constituency. The dependant variable is either turnout in the first round (t
1
)
or the difference of turnout between rounds (t
2
-t
1
). The results of the estimations through OLS
regressions are provided in table 10.
The two first columns of each date largely confirm previous results. Turnout in the fist
round is chiefly structured by socio-economic logics even though they explain only part of the
variance (about one third of the variance, in average, the adjusted R² being equal to .283 to
.465). Dominance plays no role in explaining turnout. In the second round, dominance has an
impact on turnout. The impact of dominance is besides negative on turnout. It is however
rather weak and hazardous. Despite the fact that some other variables are also more or less
significant, no explanation in variation of turnout is really achieved. Adjusted R² scores are
very low and much of the variance is not explained. In fact, turnout variation between rounds
primarily depends on the vote share of the winning party in the second round (column 3). The
larger the victory is, the lower turnout is. This result can be interpreted in to different ways.
Firstly, we can suppose that voters have better expectations about the electoral outcome than
what is offered by our index of dominance. In particular, voters actually take into account
electoral coalitions and probability of electoral transfers. Hence, domination of one party in
the first round is not a so good predictor of electoral victory (though we have shown quite
good results in part II) and domination may be also defined as the potential attraction of votes,
taking into account the issue of proximity among parties in the first round to predict results in
the second round. This may also reflects the difference between domination and closeness of
the race (domination does not primarily rely on coalition potential whereas closeness does).
Secondly, we can also suppose that that the margin of victory depends on actual turnout
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Convention