This study demonstrated the equivalence between the Rasch testlet model and the three-level one-parameter testlet model and explored the Markov Chain Monte Carlo (MCMC) method for model parameter estimation in WINBUGS. The estimation accuracy from the MCMC method was compared with those from the marginalized maximum likelihood estimation (MMLE)…

The development of statistical methods for detecting test collusion is a new research direction in the area of test security. Test collusion may be described as large-scale sharing of test materials, including answers to test items. Current methods of detecting test collusion are based on statistics also used in answer-copying detection.…

As with any psychometric models, the validity of inferences from cognitive diagnosis models (CDMs) determines the extent to which these models can be useful. For inferences from CDMs to be valid, it is crucial that the fit of the model to the data is ascertained. Based on a simulation study, this study investigated the sensitivity of various fit…

Changing the order of items between alternate test forms to prevent copying and to enhance test security is a common practice in achievement testing. However, these changes in item order may affect item and test characteristics. Several procedures have been proposed for studying these item-order effects. The present study explores the use of…

A vertical score scale is needed to measure growth across multiple tests in terms of absolute changes in magnitude. Since the warrant for subsequent growth interpretations depends upon the assumption that the scale has interval properties, the validation of a vertical scale would seem to require methods for distinguishing interval scales from…

This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

According to Kane (this issue), "the validity of a proposed interpretation or use depends on how well the evidence supports" the claims being made. Because truth and evidence are distinct, this means that the validity of a test score interpretation could be high even though the interpretation is false. As an illustration, we discuss the case of…

Kane's paper "Validating the Interpretations and Uses of Test Scores" is the most complete and clearest discussion yet available of the argument-based approach to validation. At its most basic level, validation as formulated by Kane is fundamentally a simply-stated two-step enterprise: (1) specify the claims inherent in a particular interpretation…

Kane (this issue) presents a comprehensive review of validity theory and reminds us that the focus of validation is on test score interpretations and use. In reacting to his article, I support the argument-based approach to validity and all of the major points regarding validation made by Dr. Kane. In addition, I call for a simpler, three-step…

In validating uses of testing, it is helpful to distinguish those that rely directly on the information provided by scores or score distributions ("direct" uses and consequences) versus those that instead capitalize on the motivational effects of testing, or use testing and test reporting to shape public opinion ("indirect" uses and consequences).…

To validate an interpretation or use of test scores is to evaluate the plausibility of the claims based on the scores. An argument-based approach to validation suggests that the claims based on the test scores be outlined as an argument that specifies the inferences and supporting assumptions needed to get from test responses to score-based…

Kane distinguishes between two kinds of argument: the interpretation/use argument and the validity argument. This commentary considers whether there really are two kinds of argument, two arguments, or just one. It concludes that there is just one argument: the validity argument. (Contains 2 figures and 5 notes.)

This response to the comments contains three main sections, each addressing a subset of the comments. In the first section, I will respond to the comments by Brennan, Haertel, and Moss. All of these comments suggest ways in which my presentation could be extended or improved; I generally agree with their suggestions, so my response to their…

Studies of data use illuminate ways in which education professionals have used test scores and other evidence relevant to students' learning--in action in their own contexts of work--to make decisions about their practice. These studies raise instructive challenges for a validity theory that focuses on intended interpretations and uses of test…

The interpretability of score comparisons depends on the design and execution of a sound data collection plan and the establishment of linkings between these scores. When comparisons are made between scores from two or more assessments that are built to different specifications and are administered to different populations under different…