Do we need to weight satisfaction scores with importance ratings in measuring quality of life?

Trauer and Mackinnon (2001; Quality of life research 10, pp. 579-585) recently proposed that weighting satisfaction scores by importance ratings in measuring quality of life is undesirable and unnecessary. However, they didn't use empirical data to support their claim. In this study, different weighting algorithms developed by Cummins (1997; Comprehensive Quality of Life Scale - Adult: Manual [Deakin, University Australia]), Raphael et al. (1996; Journal of Adolescent Health 19, pp. 366-375), Ferrans and Powers (1985; Advances in Nursing Science 8, pp. 15-24) and Frisch (1992; Comprehensive Casebook of Cognitive Therapy [Plenum Press, New York]) for measuring quality of life (QOL) were applied. Weighted scores computed from these weighting algorithms were compared with unweighted scores in predicting a global life satisfaction measure by correlation and moderated regression analyses. One hundred and thirty undergraduate students at National Taiwan University participated in the study voluntarily. They completed a 15-item questionnaire on quality of campus life developed by the authors. They also completed the Satisfaction with Life Scale (SWLS), a global life satisfaction measure developed by Diener et al. (1985; Journal of Personality Assessment 49, pp. 71-75). The correlation results revealed that the weighted scores computed from different algorithms didn't have higher correlations to the SWLS than the unweighted scores. The moderated regression results also revealed that item importance did not moderate the relationship between item satisfaction and the overall life satisfaction. All these findings revealed that weighting satisfaction with importance is unnecessary.