We compared coefficient alpha with five alternatives (omega total, omega RT, omega h, GLB, and coefficient H) in two simulation studies. Results showed for unidimensional scales, (a) all indices except omega h performed similarly well for most conditions; (b) alpha is still good; (c) GLB and coefficient H overestimated reliability with small…

Current procedures for equating number-correct scores using traditional item response theory (IRT) methods assume local independence. However, when tests are constructed using testlets, one concern is the violation of the local item independence assumption. The testlet response theory (TRT) model is one way to accommodate local item dependence.…

This study examines the use of cross-classified random effects models (CCrem) and cross-classified multiple membership random effects models (CCMMrem) to model rater bias and estimate teacher effectiveness. Effect estimates are compared using CTT versus item response theory (IRT) scaling methods and three models (i.e., conventional multilevel…

Broadly conceived, reliability involves quantifying the consistencies and inconsistencies in observed scores. Generalizability theory, or G theory, is particularly well suited to addressing such matters in that it enables an investigator to quantify and distinguish the sources of inconsistencies in observed scores that arise, or could arise, over…

Will subscores provide additional information than what is provided by the total score? Is there a method that can estimate more trustworthy subscores than observed subscores? To answer the first question, this study evaluated whether the true subscore was more accurately predicted by the observed subscore or total score. To answer the second…

Test homogeneity and internal consistency reliability indices were developed on the basis of theoretical considerations of properties of hierarchical structures of data matrices. This reconceptualization, in terms of ordinal test theory, has potential for explication of the mutual relationship of test reliability and homogeneity. (TJH)

It has often been asserted that the reliability of a measure places an upper limit on its validity. This article demonstrates in theory that validity can rise when reliability declines, even when validity evidence is a correlation with an acceptable criterion. Whether empirical examples can actually be found is an open question. (SLD)

The impact of item response theory (IRT) on the measurement practitioner is discussed, with a review of potential benefits. The complexity of IRT theory and procedures and the lack of robustness of IRT procedures to violation of assumptions must be recognized for the measurement practitioner to realize its advantages. (SLD)

A taxonomy of 43 rules for writing multiple-choice test items is presented, based on a consensus of 46 textbooks. These guidelines are presented as complete and authoritative, with solid consensus apparent for 33 of the rules. Four rules lack consensus, and 5 rules were cited fewer than 10 times. (SLD)

Applications of Oscar K. Buros' values and convictions to current developments in measurement are considered. Biographical information and Buros' personal philosophy on applied measurement are discussed. The Buros tradition refocuses evaluators' attention on the implications of their work for the end users of measurement results--test users and…