The Political Entropy of Vote Choice: An Empirical Test of Uncertainty Reduction
Recent literature in voting theory has developed the idea that individual
voting preferences are probabilistic rather than strictly deterministic.
This work builds upon spatial voting models (Enelow and Hinich 1981,
Ferejohn and Fiorina 1974, Davis, DeGroot and Hinich 1972, Farquharson
1969) by introducing probabilistic uncertainty into the calculus of voting
decision on an individual level. Some suggest that the voting decision
can be modeled with traditional probabilistic tools of uncertainty
(Coughlin 1990, Coughlin and Nitzen 1981). Entropy is a measure of
uncertainty that originated in statistical thermodynamics. Essentially,
entropy indicates the amount of uncertainty in probability distributions
(Soofi 1992), or it can be thought of as signifying a lack of human
knowledge about some random event (Denbigh and Denbigh, 1985). Entropy
in statistics developed with Kolmogorov (1959), Kinchin (1957), and
Shannon (1948), but has rarely been applied to social science problems.
Exceptions include Darcy and Aigner's (1980) use of entropy to analyze
categorical survey responses in political science, and economic
applications by Theil (1967) and Theil and Fiebig (1984).
I examine voters' uncertainty as they assess candidates, and measure
policy positions. I then test whether or not these voters minimize the
cost of voting (specifically the cost of information) by determining
a maximum entropy selection. Except for the inclusion of entropy terms,
this approach is similar to others in the recent literature. In this
paper I develop a measure to aggregate evaluation of issue uncertainty
and corresponding vote choice where the uncertainty parameterization is
derived from an entropy calculation on a set of salient election issues.
The primary advantage of this approach is that it requires very few
assumptions about the nature of the data. Using 1994 American National
Election Study survey data from the Center for Political Studies, I test
the hypothesis that the ``Contract with America'' reduced voter
uncertainty about the issue positions of Republican House candidates.
The entropic model suggests that voters used the written and explicit
Republican agenda as a means of reducing issue uncertainty without
substantially increasing time spent evaluating candidate positions.
Proximity Spatial Voting Model
Voting Under Uncertainty
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