Simulations were conducted to examine the effect of differential item functioning (DIF) on measurement consequences such as total scores, item response theory (IRT) ability estimates, and test reliability in terms of the ratio of true-score variance to observed-score variance and the standard error of estimation for the IRT ability parameter. The…

The usual formulas for the reliability of differences between two test scores are based on the assumption that the error scores are uncorrelated. Formulas are presented for the general case where this assumption is unnecessary. (Author/JKS)

A decision-theoretic approach to the question of reliability in categorically scored examinations is explored. The concepts of true scores and errors are discussed as they deviate from conventional psychometric definitions and measurement error in categorical scores is cast in terms of misclassifications. A reliability measure based on…

A direct proof is given for the generalized Spearman-Brown formula for any real multiple of test length. (Author)

Author supports the credibility of the propositions that: (1) the true component of a score is proportional to the number of equivalent elements that contribute to it. And, (2) the error component of a score is proportional to the square root of the number of equivalent elements that contribute to it. (Author/MB)

Presented is a detailed description of two true score confidence interval approaches, their use, interpretation, and a philosophical conflict that arises in many applied instances. (Contains 27 references.) (Author)

A derivation of a formula for the stability coefficient is presented and discussed in terms of test reliability over time. (PR)

This paper discusses the basic theory underlying confidence limits and presents reasons why psychologists should incorporate confidence ranges in their psychodiagnostic reports. Four methods for establishing confidence limits are compared. Three of the methods involve estimated true scores, and the fourth is the standard error of measurement…

A rebuttal of Frary's 1969 article in Educational and Psychological Measurement. (MS)

The general problem of using group status to estimate true scores given multiple measures is considered in this paper. (Authors)

This review of issues about correcting for attenuation concludes that the basic difficulty lies in being able to identify and equate sources of variance in estimates of validity and reliability. Recommendations are proposed for cautious use of correction for attenuation. (Author/CM)

A distinction is made between reliability of measurement and reliability of classification; the "criterion-referenced reliability coefficient" describes the former. Application of this coefficient to the probability distribution of possible scores for a single student yields a meaningful way to describe the reliability of a single score. (Author)

Given known item parameters for a test, unbiased estimators are derived for an examinee's ability parameter, his or her proportion correct true score for the variances of these parameters and for the parallel forms reliability of the maximum likelihood estimator of the ability parameter. (Author/JKS)

The importance of using the standard error of measurement (SEm) in determining reliability in test scores is emphasized. The SEm is compared to the hypothetical true score for standardized tests, and procedures for calculation of the SEm are explained. (JDD)