We propose a measure of voter ideology which combines party manifesto data compiled by
Budge, Robertson, Heari, Klingemann, and Volkens (1992) and updated by Volkens (1995),
with election return data. Assuming the comparability and relevance of left-right ideology, we
estimate the median voter position in 15 Western democracies throughout most of the
postwar period. The plausibility of our assumptions, and therefore the validity of our
measure, is supported by the results of several validity tests. With this new measure we are …