Abstract
Quality of life has drawn increasing attention in health science and more efforts have been devoted to develop instruments that are valid and reliable to assess quality of life. The World Health Organization (WHO) has devised an instrument World Health Organization Quality of Life Survey- Abbreviated Version (WHOQOL-BREF) to assess quality of life, but the psychometric property of each individual item has not been studied yet. Using item response theory, we examine the properties of the WHOQOL-BRIEF Taiwan version. Samejima’s graded response model was fitted, and item parameters were calculated. The items were ranked base on their discrimination power, and the best items are identified. Several data with subset of items (22, 20, 18, 16 and 14 items) were created by omitting items with lower discrimination power. The test information function of the full questionnaire and the subsets were compared. The results showed there were significant positive correlations between the full questionnaire and the subsets of items and the distributions are similar. The test information function showed the maximum amount of test information spaced over two ends of the theta continuum, and this suggested that the WHOQOL-BREF provided more information for groups with either lower or higher satisfaction of quality of life, while it is less discriminating for individuals in the middle range.
Similar content being viewed by others
References
Baker F.B. (1992). Item Response Theory: Parameter Estimation Techniques. M. Dekker, New York
Bock R.D., Aitken M. (1981). Marginal maximum likelihood estimation of item parameters: application of an EM algorithm. Psychometrika 46: 443–445
Bonomi A.E., Patrick D.L., Bushnell D.M., Martin M. (2000). Validation of the United States’ version of the World Health Organization Quality of Life (WHOQOL) instrument. Journal of Clinical Epidemiology 53: 1–12
DeGirolamo G., Rucci P., Scocco P., Becchi A., Coppa F., D’Addario A., Daru E., De Leo D., Galassi L., Mangelli L., Marson C., Neri G., Soldani L. (2000). Quality of life assessment: validation of the Italian version of the WHOQOL-Brief. Epidemiology Psichiatry Society 9: 45–55
DeLeeuw J., Verhelst N. (1986). Maximum likelihood estimation in generalized Rasch models. Journal of Educational Statistics 11: 183–196
Dempster A.P., Laird N.M., Rubin D.B. (1977). Maximum likelihood from incomplete data via the EM algorithm (with discussion). Journal of the Royal Statistical Society, Series B 39: 1–38
Hambleton R.K., Swaminathan H., Rogers H.J. (1991). Fundamentals of Item Response Theory. Sage, Newbury Park, CA
Herche J., Engelland B. (1996). Reversed-polarity items and scale uni-dimensionality. Journal of the Academy of Marketing Science 24: 366–374
Holland P.W. (1990). On the sampling theory foundations of item response theory models. Psychometrika 55: 577–601
Min S.K., Kim K.I., Lee C.I., Jung Y.C., Suh S.Y., Kim D.K. (2002). Development of the Korean versions of WHO Quality of Life scale and WHOQOL-BREF. Quality of Life Research 11: 593–600
Muraki E., Bock R.D. (1996). PARSCALE: IRT based Test Scoring and Item Analysis for Graded Open-ended Exercises and Performance Tasks, Version 3. Scientific Software International Inc, Chicago
Norholm V., Bech P. (2001). The WHO Quality of Life (WHOQOL) Questionnaire: Danish validation study. Nordic Journal of Psychiatry 55: 229–235
Samejima F. (1967). Estimation of latent ability using a response pattern of graded scores. Psychometrika Monograph Supplement 34: 100–114
Skevington S.M., Bradshawa J., Saxenab S. (1999). Selecting national items for the WHOQOL: conceptual and psychometric considerations. Social Science and Medicine 48: 473–487
Thissen D. (1981). MULTILOGTM User’s Guide. Multiple Categorical Item Analysis and Test Scoring Using Item Response Theory, Version 6.0. Scientific Software, Chicago, Illinois
World Health Organization (1993). WHOQOL Study Protocol. WHO, Geneva, (MNH/PSF/93.9)
World Health Organization (1994). WHOQOL Protocol for New Centers. WHO, Geneva
Yao G., Chung C.W., Yu C.F., Wang J.D. (2002). Development and verification of validity and reliability of the WHOQOL-BREF Taiwan version. Journal of the Formosan Medical Association 101: 342–351
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lin, T.H. Identifying Optimal Items in Quality of Life Assessment. Qual Quant 41, 661–672 (2007). https://doi.org/10.1007/s11135-006-9017-7
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11135-006-9017-7