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Psychometric Properties of IRT Proficiency Estimates
Author(s) -
Kolen Michael J.,
Tong Ye
Publication year - 2010
Publication title -
educational measurement: issues and practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.158
H-Index - 52
eISSN - 1745-3992
pISSN - 0731-1745
DOI - 10.1111/j.1745-3992.2010.00179.x
Subject(s) - estimator , item response theory , statistics , bayes' theorem , mathematics , bayes estimator , econometrics , bayesian probability , psychometrics , reliability (semiconductor) , power (physics) , physics , quantum mechanics
Psychometric properties of item response theory proficiency estimates are considered in this paper. Proficiency estimators based on summed scores and pattern scores include non‐Bayes maximum likelihood and test characteristic curve estimators and Bayesian estimators. The psychometric properties investigated include reliability, conditional standard errors of measurement, and score distributions. Four real‐data examples include (a) effects of choice of estimator on score distributions and percent proficient, (b) effects of the prior distribution on score distributions and percent proficient, (c) effects of test length on score distributions and percent proficient, and (d) effects of proficiency estimator on growth‐related statistics for a vertical scale. The examples illustrate that the choice of estimator influences score distributions and the assignment of examinee to proficiency levels. In particular, for the examples studied, the choice of Bayes versus non‐Bayes estimators had a more serious practical effect than the choice of summed versus pattern scoring.