Figure 4.

Precision of the 10-item OA-FUNCTION-CAT compared with the WOMAC scales as measured by standard errors of scale scores. (a) 10-item OA-FUNCTION-CAT functional difficulty and WOMAC physical function scales. (b) 10-item OA-FUNCTION-CAT functional pain and WOMAC pain scales. CAT, computer adaptive test; OA, osteoarthritis; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.