In: Calitatea Vieţii, 17(1-2), 153-170. Abstract: Life satisfaction, a global cognitive
evaluation of one’s life, is a very frequently used indicator in quality of
life research. This construct is usually measured by simple scales, differing
one from another by the phrasing of questions and by the number of answer
categories. Giving the
need for international
comparison of levels
of subjective well-being, international comparative programs were
initiated that contains surveys conducted
almost simultaneously, with
the same methodology. These surveys
are very expensive and cannot be conducted as frequently as needed. An
alternative is the homogenization of survey data from different national level
programs. The main impediment is the variation in the length of the scales,
those with 3, 4, 5, 7 or 11 categories being most frequently used. This brings
the need for testing procedures for transformation of these scales. The
objective of this paper is to review the methodological backgrounds of such a
process, highlighting the signification and possible errors induced by the
attributions of scores to the categories of ordinal-level variables. We propose
an exercise of transforming an ordinal scale with 5 categories, used in
Diagnosis of Quality of Life research program organized by Romanian Institute
for Quality of Life to an 11-scale pseudo-interval scale, frequently used in
international research programs. Several translation strategies are presented
from the simplest, i.e. conventional linear transformation, to the most
sophisticated-like estimation from the observed frequencies and distributional
assumption, transformation by expert ratings and regression with optimal
scaling. Finally, methods are comparatively evaluated and recommendations for
researchers are formulated. Download: PDF |
Content >
