representation and electoral systems - American Political Science ...

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complexity of most electoral systems in practice, but the choice is analytically and
practically sound. Analytically, it facilitates the construction of a parsimonious
predictive model and helps to clarify the logic, dynamics and outcomes of electoral
systems, not a mean feat because this is invaluable information for constructing
predictive models of more complex electoral systems, such as, for example, mixed
parallel and compensatory systems as well as other institutional permutations.
Practically, it helps to identify for time-constrained practitioners the core institutional
components of electoral systems and clarify their consequences for party systems and
cabinet duration.
An innovative variable that underscores the predictive power of the simple electoral
systems model is vintage Taagepera. Inspired by Colomer’s “micro-mega” rule – “the
small prefer the large, and the large prefer the small,” (Colomer 2004: 3) – the seat
product of simple electoral systems (M F S) is obtained by multiplying the assembly size
(S) by the number of seats in the average district (or the mean district magnitude M), with
M modulated by the seat allocation “formula exponent” (F). The predictive power of the
seat product rests on the fact that it is a combined summary expression of the three
components of simple electoral systems, assembly size, district magnitude and electoral
formula. It represents the “comprehensive outcome of (Taagepera) trying to make sense
of electoral systems for over 40 years” (p. 92).
Simple electoral systems predict average outcomes. This may not be entirely satisfactory
if one is looking for predictive precision, but it is consistent with the requirements of
conceptual parsimony and analytical rigor that facilitate the development of predictive
models. Moreover, the predictions derived from the simple electoral system model
conform, on average, to observed global patterns. Taagepera’s deductive approach thus
holds up well against empirical evidence.
Seats and Votes is one the most widely cited books and has inspired many of the best
works in comparative electoral systems research. But its non-statistical approach has not
been widely emulated in the field. Predicting Party Sizes may very well suffer the same
paradoxical fate. There is no small irony in this. Within its narrowly defined focus on
simple electoral systems, it has achieved the scientific ideals of cumulative theory
building and prediction that motivated the behavioral revolution in political science over
fifty years ago. But this accomplishment has come at a time when the emphasis in
political science has shifted toward more context-sensitive theorizing. But even here,
Predicting Party Sizes contains important insights. The unfinished Duvergerian agenda
noted by Taagepera involves, among other things, clarifying the microfoundations of
simple electoral systems, which requires tackling the thorniest of contextual variables,
political culture and its relationship to the psychological effects of electoral systems and
the resulting strategic calculations of political actors. And if Taagepera’s disciplined
approach motivates and informs theory-building in this endeavor, then Predicting Party
Sizes could share another fate with Seats and Votes. In 1999, Seats and Votes won the
George H. Hallett award (Disclosure: I chaired the award committee). It should not a be surprise if
Predicting Party Sizes is a strong contender for the same award a decade from now