K. Bollen, LIBERAL DEMOCRACY - VALIDITY AND METHOD FACTORS IN CROSS-NATIONAL MEASURES, American journal of political science, 37(4), 1993, pp. 1207-1230
This paper examines the definition and measurement of liberal democrac
y. Specifically, my purposes are (1) to propose a working definition o
f liberal democracy; (2) to outline a theory of ''method factors'' in
subjective measures of liberal democracy; (3) to provide the first est
imates of the proportion of variance due to systematic error, validity
, and random error in commonly used measures; (4) to replicate these r
esults across several years; and (5) to estimate the degree of liberal
democracy in more than 150 countries. All but one measure contain sys
tematic error, and in some cases the bias component is large. Furtherm
ore, a new liberal democracy index has a .96 squared correlation with
the liberal democracy latent variable and has negligible correlations
with the method factors that are present in the individual indicators.
The results suggest that the current practice of treating unadjusted
democracy indicators as error free can be misleading.