Improving the Quality and Applicability of the Dutch Scales of the Communication Profile for the Hearing Impaired Using Item Response Theory PurposeThe aim of this study was to improve the quality and applicability of the 6 Dutch scales of the Communication Profile for the Hearing Impaired (CPHI; Demorest & Erdman, 1986, 1987, 1988) using item response theory (IRT). IRT modeling can produce precise, valid, and relatively brief instruments, resulting in minimal ... Article
Article  |   June 01, 2010
Improving the Quality and Applicability of the Dutch Scales of the Communication Profile for the Hearing Impaired Using Item Response Theory
 
Author Affiliations & Notes
  • Lidwine B. Mokkink
    VU University Medical Center, Amsterdam, the Netherlands
  • Dirk L. Knol
    VU University Medical Center, Amsterdam, the Netherlands
  • Ruth M. A. van Nispen
    VU University Medical Center, Amsterdam, the Netherlands
  • Sophia E. Kramer
    VU University Medical Center, Amsterdam, the Netherlands
  • Contact author: Lidwine B. Mokkink, EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, the Netherlands. E-mail: w.mokkink@vumc.nl.
Article Information
Hearing Disorders / Special Populations / Cultural & Linguistic Diversity / Hearing
Article   |   June 01, 2010
Improving the Quality and Applicability of the Dutch Scales of the Communication Profile for the Hearing Impaired Using Item Response Theory
Journal of Speech, Language, and Hearing Research, June 2010, Vol. 53, 556-571. doi:10.1044/1092-4388(2010/09-0035)
History: Received February 18, 2009 , Revised August 6, 2009 , Accepted February 1, 2010
 
Journal of Speech, Language, and Hearing Research, June 2010, Vol. 53, 556-571. doi:10.1044/1092-4388(2010/09-0035)
History: Received February 18, 2009; Revised August 6, 2009; Accepted February 1, 2010
Web of Science® Times Cited: 11

PurposeThe aim of this study was to improve the quality and applicability of the 6 Dutch scales of the Communication Profile for the Hearing Impaired (CPHI; Demorest & Erdman, 1986, 1987, 1988) using item response theory (IRT). IRT modeling can produce precise, valid, and relatively brief instruments, resulting in minimal response burden (Edelen & Reeve, 2006).

MethodWe investigated (a) whether items fit to the graded response model (GRM; Samejima, 1969) using Stone and Zhang’s (2003)  procedure to test goodness of fit and (b) whether items showed differential item functioning (DIF) with the IRT log-likelihood ratio approach for 5 group variables: gender, age, living arrangement, use of hearing aids, and degree of hearing impairment. We investigated the magnitude of DIF by calculating the maximum difference between expected item scores for subgroups of the group variables of items showing DIF.

ResultsIn a cross-sectional study, 408 consecutive individuals with hearing impairment completed the Dutch CPHI scales. Twelve items were deleted because of misfit to GRMs, 14 items showed uniform DIF, and 2 showed nonuniform DIF. Five items showing DIF were deleted due to large magnitude of DIF. The short form of the Dutch CPHI scales contains 35 items.

ConclusionsDIF analyses showed that the short form was relatively free of DIF with respect to the 5 group variables. Hence, there is no need to make adjustments for the calculation of subgroup scores.

Acknowledgments
This study was financially supported by the Foundation NutsOHRA. We are grateful to Lucien Antheunis and Nele Corstjens from the University Hospital in Maastricht for their contribution to the data collection and to Esther Bijpost for her assistance. We also acknowledge the helpful comments of the Clinimetric Working Group of the EMGO Institute for Health and Care Research (VU University Medical Center, Amsterdam, the Netherlands), chaired by Riekie de Vet, and of the reviewers. Among them was Marilyn E. Demorest. The CPHI copyright is held by Marilyn E. Demorest and Sue Ann Erdman; we received their permission to translate seven CPHI scales into Dutch.
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