Differential item functioning was negligible in an adaptive test of functional status for patients with knee impairments who spoke English or Hebrew

Abstract

Statistically significant DIF was identified in some items but represented negligible clinical impact. Results suggested no need to adjust items for DIF when assessing FS outcomes across groups of patients with knee impairments who answer the knee CAT items in English in the United States or Hebrew in Israel. These findings suggest negligible differences in cultural perceptions between English and Hebrew wording of these knee-specific CAT FS items.

Association Between Directional Preference and Centralization in Patients With Low Back Pain

“…11,12,24,25,33,64 The primary benefits of a computerized adaptive test are efficient data collection (ie, reduced respondent burden), with little loss of measurement precision and ability to automatically integrate diverse data sets (eg, an integrated electronic outcomes process with electronic health records).…”

Single-item screens identified patients with elevated levels of depressive and somatization symptoms in outpatient physical therapy

“…Remaining items were assessed for differential item functioning between selected clinically logical groups of patients know to have different functional status outcomes [23] following methods previously described [6,[45][46][47]. Briefly, differential item functioning is present when the relationship between item responses and the trait measured by the test differs systematically between groups of patients after controlling for the patient's underlying abilities [19].…”

“…In some samples, particularly large samples, differential item functioning might be detected (significant) but be of little practical importance [46,47]. So, before progressing sequentially to the next variable for differential item functioning assessment, we assessed the correlation between unadjusted ability estimates and differential item functioning-adjusted ability estimates, and we assessed the magnitude of the differences between unadjusted and differential item functioning-adjusted ability estimates.…”

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