Composite scores are often formed from test scores on educational achievement test batteries to provide a single index of achievement over two or more content areas or two or more item types on that test. Composite scores are subject to measurement error, and as with scores on individual tests, the amount of error variability typically depends on…

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…

This paper illustrates that the psychometric properties of scores and scales that are used with mixed-format educational tests can impact the use and interpretation of the scores that are reported to examinees. Psychometric properties that include reliability and conditional standard errors of measurement are considered in this paper. The focus is…

Presents an Item Response Theory (IRT) method for estimating standard errors of measurement of scale scores for the situation in which scale scores are nonlinear transformations of number-correct scores. Also describes procedures for estimating the average conditional standard error of measurement for scale scores and the reliability of scale…

Describes procedures for calculating conditional standard error of measurement (CSEM) and reliability of scale scores and classification of consistency of performance levels. Applied these procedures to data from the American College Testing Program's Work Keys Writing Assessment with sample sizes of 7,097, 1,035, and 1,793. Results show that the…

This paper compares modified Guttman and item response theory (IRT) based procedures for classifying examinees in ordered levels when each level is represented by several multiple choice test items. In the modified Guttman procedure, within-level number correct scores are mapped to binary level mastery scores. Examinees are then assigned to levels…

Developed a procedure for defining achievement levels on continuous scales using aspects of Guttman scaling (L. Guttman, 1950) and Item Response Theory. Using data from high school mathematics tests for about 6,000 students, found the new procedure to have higher reliability, higher classification consistency, and lower classification error than…

The application of latent trait theory to classroom tests necessitates the use of small sample sizes for parameter estimation. Computer generated data were used to assess the accuracy of estimation of the slope and location parameters in the two parameter logistic model with fixed abilities and varying small sample sizes. The maximum likelihood…

A procedure is described for estimating the reliability and conditional standard errors of measurement of scale scores incorporating the discrete transformation of raw scores to scale scores. The method is illustrated using a strong true score model, and practical applications are described. (SLD)

The reliabilities of 6 item bias indices and correlations among them were investigated for each of the 11 tests of the Iowa Tests of Basic Skills (ITBS). The difficulty and delta indices detected group differences in relative item difficulty. Biserial and point biserial indices detected group differences in item discrimination. The Scheuneman and…