The R software provides packages and functions that provide data analysis in classical true score, generalizability theory, item response theory, and Rasch measurement theories. A brief list of notable articles in each measurement theory and the first measurement journals is followed by a list of R psychometric software packages. Each psychometric…

Peer-grading is commonly adopted by instructors as an effective assessment method for MOOCs (Massive Open Online Courses) and SPOCs (Small Private online course). For solving the problems brought by varied skill levels and attitudes of online students, statistical models have been proposed to improve the fairness and accuracy of peer-grading.…

This report introduces a short, hands-on activity that addresses a key challenge in teaching quantitative methods to students who lack confidence or experience with statistical analysis. Used near the beginning of the course, this activity helps students develop an intuitive insight regarding a number of abstract concepts which are key to…

This article provides a brief description of a Windows application called IRTEQ. IRTEQ employs an intuitive, user-friendly graphic user interface that can rescale one test form to another by using various item response theory (IRT) scaling methods. It supports various IRT models for test forms. It can also equate test scores on the scale of one…

A new measure for reliability of a rating scale is introduced, based on the classical definition of reliability, as the ratio of the true score variance and the total variance. Clinical trial data can be employed to estimate the reliability of the scale in use, whenever repeated measurements are taken. The reliability is estimated from the…

Presents and illustrates an appropriate formula for correction for attenuation that can be used in situations in which one measure includes another measure as its part. The formula can be used for computing the correlation coefficient for true scores between total test and part test. (SLD)

A hands-on activity is described in which students attempt to measure something that they cannot see. In small groups, students estimate the number of marbles in sealed boxes. Next, students' estimates are compared with the actual numbers. Last, values from both the students' estimates and actual numbers are used to explain measurement theory and…

Describes an idiosyncracy of the MULTILOG (D. Thissen, 1991) parameter estimation process discovered during a simulation study involving the graded response model. A misordering reflected in boundary function location parameter estimates resulted in a large negative contribution to the true score followed by a large positive contribution. These…

Gives an account of classical test theory that shows how it can be viewed as a mean and variance approximation to a general version of item response theory and then shows how this approach can give insight into predicting the true score of a test and the true scores of tests not necessarily parallel to the given test. (SLD)

Proposes true score models that can account for correlated errors and their effect on coefficient alpha. These models allow random measurement errors on earlier items to affect directly or indirectly the scores on later items. Conditions under which coefficient alpha may yield spuriously high estimates or reliability are discussed. (SLD)

This paper provides formulas for expected true-score measures and reliability of binary items as a function of their Rasch difficulty parameters when the trait distribution is normal or logistic. With the proposed formula, one can evaluate the theoretical values of classical reliability indexes for norm-referenced and criterion-referenced…

Proposes formulas for expected true-score measures and reliability of binary items as a function of their Rasch difficulty when the trait (ability) distribution is normal or logistic. Provides an illustrative example for using the proposed formulas. (SLD)

Proposes a new regression correction for the SIBTEST statistical tests (R. Shealy and W. Stout, 1993) that essentially uses a two-segment piecewise linear regression of the true on observed matching subtest scores. A simulation study illustrates the approach. (SLD)

This paper provides analytic evaluations of expected (marginal) true-score measures for binary items given their item response theory (IRT) calibration. Under the assumption of normal trait distributions, marginalized true scores, error variance, true score variance, and reliability for norm-referenced and criterion-references interpretations are…

Exact formulas for classical error variance are provided for Rasch measurement with logistic distributions. An approximation formula with the normal ability distribution is also provided. With the proposed formulas, the additive contribution of individual items to the population error variance can be determined without knowledge of the other test…