ERIC Number: EJ1030024
Record Type: Journal
Publication Date: 2014
Abstractor: As Provided
Reference Count: N/A
IRT-Estimated Reliability for Tests Containing Mixed Item Formats
Shu, Lianghua; Schwarz, Richard D.
Journal of Educational Measurement, v51 n2 p163-177 Sum 2014
As a global measure of precision, item response theory (IRT) estimated reliability is derived for four coefficients (Cronbach's a, Feldt-Raju, stratified a, and marginal reliability). Models with different underlying assumptions concerning test-part similarity are discussed. A detailed computational example is presented for the targeted coefficients. A comparison of the IRT model-derived coefficients is made and the impact of varying ability distributions is evaluated. The advantages of IRT-derived reliability coefficients for problems such as automated test form assembly and vertical scaling are discussed.
Descriptors: Item Response Theory, Reliability, Models, Computation, Comparative Analysis, Scaling, Statistical Distributions
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Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
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