01-02-2008
A generalizability study of the Norwegian version of KINDLR in a sample of healthy adolescents
Gepubliceerd in: Quality of Life Research | Uitgave 1/2008
Log in om toegang te krijgenAbstract
Purpose
The aim in the present study was to illustrate generalizability theory by exploring some psychometric aspects of the Norwegian version of KINDLR (KINDL-N). This questionnaire is a measure of quality of life in adolescents. It consists of 24 items arranged in six subscales or aspects, corresponding to six domains of adolescents’ health-related quality of life.
Method
A total of 239 healthy adolescents completed the questionnaire. The analysis was performed in line with generalization theory, and this analysis yields among other things so-called generalizability and dependability coefficients, which are analogous to reliability coefficients in classical test theory. The preferred design was a mixed two-facet design, with the six aspects as a fixed facet and the items nested within aspects as a random facet. For comparison, a random two-facet design and a one-facet design were also analyzed.
Results
The generalizability and dependability coefficients for KINDL-N are satisfactory, but the coefficients can be markedly improved by increasing the length of the instrument while keeping it to a manageable size. The mixed two-facet design resulted in somewhat higher coefficients than a one-facet design and much higher coefficients than a random two-facet design.
Conclusion
If the items within a questionnaire are arranged in distinct subscales, a two-facet design analyzed by generalizability theory gives more sophisticated results than classical test theory. Moreover, the results may depend considerably on whether a mixed or random two-facet design is chosen. Hence, the choice of an appropriate measurement design in line with the intended use of the questionnaire is essential.