caa a22 4500 606177922 CHVBK 20210128100754.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s11136-013-0540-4 doi (NATIONALLICENCE)springer-10.1007/s11136-013-0540-4 Quantifying ‘problematic' DIF within an IRT framework: application to a cancer stigma index [Elektronische Daten] [Maria Edelen, Brian Stucky, Anita Chandra] Purpose: DIF detection within an IRT framework is highly powerful, often identifying significant DIF that is of little clinical importance. This paper introduces two metrics for IRT DIF evaluation that can discern potentially problematic DIF among items flagged with statistically significant DIF. Methods: Computation of two DIF metrics—(1) a weighted area between the expected score curves (wABC) and (2) a difference in expected a posteriori scores across item response categories (dEAP)—is described. Their use is demonstrated using data from a 27-item cancer stigma index fielded to four adult samples: (1) Arabic (N=633) and (2) English speakers (N=324) residing in Jordan and Egypt, and (3) English (N=500) and (4) Mandarin speakers (N=500) residing in China. We used IRTPRO's DIF module to calculate IRT-based Wald chi-square DIF statistics according to language within each region. After standard p value adjustments for multiple comparisons, we further evaluated DIF impact with wABC and dEAP. Results: There were a total of twenty statistically significant DIF comparisons after p value adjustment. The wABCs for these items ranged from 0.13 to 0.90. Upon inspection of curves, DIF comparisons with wABCs >0.3 were deemed potentially problematic and were considered further for removal. The dEAP metric was also informative regarding impact of DIF on expected scores, but less consistently useful for narrowing down potentially problematic items. Conclusions: The calculations of wABC and dEAP function as DIF effect size indicators. Use of these metrics can substantially augment IRT DIF evaluation by discerning truly problematic DIF items among those with statistically significant DIF. RAND Corporation, 2013 IRT nationallicence DIF nationallicence IRT DIF evaluation nationallicence wABC nationallicence dEAP nationallicence Edelen Maria RAND Corporation, 20 Park Plaza Suite 920, 02116, Boston, MA, USA aut Stucky Brian RAND Corporation, 1776 Main Street, P.O. Box 2138, 90407-2138, Santa Monica, CA, USA aut Chandra Anita RAND Corporation, 1200 South Hayes Street, 22202-5050, Arlington, VA, USA aut Quality of Life Research Springer International Publishing 24/1(2015-01-01), 95-103 0962-9343 24:1<95 2015 24 11136 https://doi.org/10.1007/s11136-013-0540-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11136-013-0540-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Edelen Maria RAND Corporation, 20 Park Plaza Suite 920, 02116, Boston, MA, USA aut NATIONALLICENCE 700 1- Stucky Brian RAND Corporation, 1776 Main Street, P.O. Box 2138, 90407-2138, Santa Monica, CA, USA aut NATIONALLICENCE 700 1- Chandra Anita RAND Corporation, 1200 South Hayes Street, 22202-5050, Arlington, VA, USA aut NATIONALLICENCE 773 0- Quality of Life Research Springer International Publishing 24/1(2015-01-01), 95-103 0962-9343 24:1<95 2015 24 11136