A Critique of Raju and Oshima's Prophecy Formulas for Assessing the Reliability of Item Response Theory-Based Ability Estimates

Autor/in	Wang, Wen-Chung
Titel	A Critique of Raju and Oshima's Prophecy Formulas for Assessing the Reliability of Item Response Theory-Based Ability Estimates
Quelle	In: Applied Psychological Measurement, 32 (2008) 3, S.261-266 (6 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0146-6216
DOI	10.1177/0146621607306708
Schlagwörter	Test Reliability; Item Response Theory; Computation; Evaluation Methods; Test Validity; Test Construction; Bias; Evaluation Research; Equations (Mathematics) + Suchen Sie Ihr Suchwort? Testreliabilität; Item-Response-Theorie; Testvalidität; Testaufbau; Evaluationsforschung; Equations; Mathematics; Gleichungslehre
Abstract	Raju and Oshima (2005) proposed two prophecy formulas based on item response theory in order to predict the reliability of ability estimates for a test after change in its length. The first prophecy formula is equivalent to the classical Spearman-Brown prophecy formula. The second prophecy formula is misleading because of an underlying false assumption. It can yield negative reliability estimates, especially if the reliability of ability estimates for the old test is low and the new test is shorter. This article identifies the fallacy of the second prophecy formula and demonstrates the scope of its bias in predicting test reliability. (Contains 1 figure.) (Author).
Anmerkungen	SAGE Publications. 2455 Teller Road, Thousand Oaks, CA 91320. Tel: 800-818-7243; Tel: 805-499-9774; Fax: 800-583-2665; e-mail: journals@sagepub.com; Web site: http://sagepub.com
Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10