Despite the differences between contextual description and classification, both forms
of activity contribute to the next objective of comparison, hypothesis-testing. In
other words, once things have been described and classified, the comparativist
can then move on to search for those factors that may help explain what has been
described and classified. Since the 1950s, political scientists have increasingly sought
to use comparative methods to help build more complete theories of politics.
Comparison of countries allows rival explanations to be ruled out and hypotheses
derived from certain theoretical perspectives to be tested. Scholars using this mode
of analysis, which is often seen as the raison d'etre of the 'new' comparative politics
(Mayer 1989), identify important variables, posit relationships to exist between
them, and illustrate these relationships comparatively in an effort to generate and
build comprehensive theories.
Arend Lijphart (1975) claims that comparison allows 'testing hypothesized
empirical relationships among variables'. Similarly, Peter Katzenstein argues that
'comparative research is a focus on analytical relationships among variables validated
by social science, a focus that is modified by differences in the context in which we
observe and measure those variables' (in Kohli et al. 1995: 11). Finally, Mayer (1989:
46) argues somewhat more forcefully that 'the unique potential of comparative
analysis lies in the cumulative and incremental addition of system-level attributes to
existing explanatory theory, thereby making such theory progressively more
complete'. The symposia on comparative politics in World Politics (Kohli et ale 1995)
and the American Political Science Review (vol. 89, no. 2, pp. 454-481), suggest that
questions of theory, explanation, and the role of comparison are at the forefront of
scholars' minds.