Replenishing a computerized adaptive test of patient-reported daily activity functioning
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- Haley, S.M., Ni, P., Jette, A.M. et al. Qual Life Res (2009) 18: 461. doi:10.1007/s11136-009-9463-5
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Computerized adaptive testing (CAT) item banks may need to be updated, but before new items can be added, they must be linked to the previous CAT. The purpose of this study was to evaluate 41 pretest items prior to including them into an operational CAT.
We recruited 6,882 patients with spine, lower extremity, upper extremity, and nonorthopedic impairments who received outpatient rehabilitation in one of 147 clinics across 13 states of the USA. Forty-one new Daily Activity (DA) items were administered along with the Activity Measure for Post-Acute Care Daily Activity CAT (DA-CAT-1) in five separate waves. We compared the scoring consistency with the full item bank, test information function (TIF), person standard errors (SEs), and content range of the DA-CAT-1 to the new CAT (DA-CAT-2) with the pretest items by real data simulations.
We retained 29 of the 41 pretest items. Scores from the DA-CAT-2 were more consistent (ICC = 0.90 versus 0.96) than DA-CAT-1 when compared with the full item bank. TIF and person SEs were improved for persons with higher levels of DA functioning, and ceiling effects were reduced from 16.1% to 6.1%.
Item response theory and online calibration methods were valuable in improving the DA-CAT.
KeywordsOutcomes assessment Quality of life Item response theory Activities of daily living (ADL)
Activities of daily living
Activity Measure for Post-Acute Care
Computerized adaptive testing
Confirmatory factor analyses
Comparative fit index
Original Daily Activity item bank in the CAT
New expanded item bank with pretest items in the new CAT version
Differential item functioning
Generalized partial credit model
Intraclass correlation coefficient
Item response theory
Root-mean-square error of approximation
Test information function