TY - JOUR T1 - IRT health outcomes data analysis project: an overview and summary JF - Quality of Life Research Y1 - 2007 A1 - Cook, K. F. A1 - Teal, C. R. A1 - Bjorner, J. B. A1 - Cella, D. A1 - Chang, C-H. A1 - Crane, P. K. A1 - Gibbons, L. E. A1 - Hays, R. D. A1 - McHorney, C. A. A1 - Ocepek-Welikson, K. A1 - Raczek, A. E. A1 - Teresi, J. A. A1 - Reeve, B. B. KW - *Data Interpretation, Statistical KW - *Health Status KW - *Quality of Life KW - *Questionnaires KW - *Software KW - Female KW - HIV Infections/psychology KW - Humans KW - Male KW - Neoplasms/psychology KW - Outcome Assessment (Health Care)/*methods KW - Psychometrics KW - Stress, Psychological AB - BACKGROUND: In June 2004, the National Cancer Institute and the Drug Information Association co-sponsored the conference, "Improving the Measurement of Health Outcomes through the Applications of Item Response Theory (IRT) Modeling: Exploration of Item Banks and Computer-Adaptive Assessment." A component of the conference was presentation of a psychometric and content analysis of a secondary dataset. OBJECTIVES: A thorough psychometric and content analysis was conducted of two primary domains within a cancer health-related quality of life (HRQOL) dataset. RESEARCH DESIGN: HRQOL scales were evaluated using factor analysis for categorical data, IRT modeling, and differential item functioning analyses. In addition, computerized adaptive administration of HRQOL item banks was simulated, and various IRT models were applied and compared. SUBJECTS: The original data were collected as part of the NCI-funded Quality of Life Evaluation in Oncology (Q-Score) Project. A total of 1,714 patients with cancer or HIV/AIDS were recruited from 5 clinical sites. MEASURES: Items from 4 HRQOL instruments were evaluated: Cancer Rehabilitation Evaluation System-Short Form, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, Functional Assessment of Cancer Therapy and Medical Outcomes Study Short-Form Health Survey. RESULTS AND CONCLUSIONS: Four lessons learned from the project are discussed: the importance of good developmental item banks, the ambiguity of model fit results, the limits of our knowledge regarding the practical implications of model misfit, and the importance in the measurement of HRQOL of construct definition. With respect to these lessons, areas for future research are suggested. The feasibility of developing item banks for broad definitions of health is discussed. VL - 16 SN - 0962-9343 (Print) N1 - Cook, Karon FTeal, Cayla RBjorner, Jakob BCella, DavidChang, Chih-HungCrane, Paul KGibbons, Laura EHays, Ron DMcHorney, Colleen AOcepek-Welikson, KatjaRaczek, Anastasia ETeresi, Jeanne AReeve, Bryce B1U01AR52171-01/AR/United States NIAMSR01 (CA60068)/CA/United States NCIY1-PC-3028-01/PC/United States NCIResearch Support, N.I.H., ExtramuralNetherlandsQuality of life research : an international journal of quality of life aspects of treatment, care and rehabilitationQual Life Res. 2007;16 Suppl 1:121-32. Epub 2007 Mar 10. ER - TY - JOUR T1 - Simulated computerized adaptive test for patients with shoulder impairments was efficient and produced valid measures of function JF - Journal of Clinical Epidemiology Y1 - 2006 A1 - Hart, D. L. A1 - Cook, K. F. A1 - Mioduski, J. E. A1 - Teal, C. R. A1 - Crane, P. K. KW - computerized adaptive testing KW - Flexilevel Scale of Shoulder Function KW - Item Response Theory KW - Rehabilitation AB -
Background and Objective: To test unidimensionality and local independence of a set of shoulder functional status (SFS) items,
develop a computerized adaptive test (CAT) of the items using a rating scale item response theory model (RSM), and compare discriminant validity of measures generated using all items (qIRT) and measures generated using the simulated CAT (qCAT).
Study Design and Setting: We performed a secondary analysis of data collected prospectively during rehabilitation of 400 patients
with shoulder impairments who completed 60 SFS items.
Results: Factor analytic techniques supported that the 42 SFS items formed a unidimensional scale and were locally independent. Except for five items, which were deleted, the RSM fit the data well. The remaining 37 SFS items were used to generate the CAT. On average, 6 items on were needed to estimate precise measures of function using the SFS CAT, compared with all 37 SFS items. The qIRT and qCAT measures were highly correlated (r 5 .96) and resulted in similar classifications of patients.
Conclusion: The simulated SFS CAT was efficient and produced precise, clinically relevant measures of functional status with good
discriminating ability.