TitleSimulated computerized adaptive test for patients with shoulder impairments was efficient and produced valid measures of function
Publication TypeJournal Article
Year of Publication2006
AuthorsHart, DL, Cook, KF, Mioduski, JE, Teal, CR, Crane, PK
JournalJournal of Clinical Epidemiology
Publication LanguageEnglish
Keywordscomputerized adaptive testing, Flexilevel Scale of Shoulder Function, Item Response Theory, Rehabilitation

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.