Title: DIF items effects on Kuder-Richardson 20 formula and construct validity: an exploration using the Mantel-Haenszel method

Authors: Mahmoud Alquraan

Addresses: Department of Counseling and Educational Psychology, College of Education, Yarmouk University, Irbid, Jordan

Abstract: This study aims to explore the effect of DIF items detected by Mantel-Haenszel (MH) method on the reliability (KR₂₀) and construct validity (internal structure) of test scores. The current study used a verbal ability test developed by Enab (1994) for Jordanian students of the age group (9-12) years. The test consists of 40 multiple-choice items distributed to seven subtests, and it was distributed to (758) students. Results show that removing DIF test items does not have a statistical effect on the reliability coefficient (KR₂₀). The confirmatory factor analysis provides evidence that removing DIF items detected by MH leads to better construct validity (internal structure) of the test scores.

Keywords: Mantel-Haenszel method; differential item functioning; DIF; construct validity; reliability; test scores; verbal ability tests; Jordan; confirmatory factor analysis; CFA.

DOI: 10.1504/IJQRE.2016.082393

International Journal of Quantitative Research in Education, 2016 Vol.3 No.4, pp.266 - 276

Received: 11 Dec 2015
Accepted: 02 Aug 2016
Published online: 22 Feb 2017 *

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