Vertical scaling is used to put tests of different difficulty onto a common metric. The Rasch model is often used to perform vertical scaling, despite its strict functional form. Few, if any, studies have examined anchor item choice when using the Rasch model to vertically scale data that do not fit the model. The purpose of this study was to…

In educational testing, differential item functioning (DIF) statistics must be accurately estimated to ensure the appropriate items are flagged for inspection or removal. This study showed how using the Rasch model to estimate DIF may introduce considerable bias in the results when there are large group differences in ability (impact) and the data…

The software program DIMTEST can be used to assess the unidimensionality of item scores. The software allows the user to specify a guessing parameter. Using simulated data, the effects of guessing parameter specification for use with the ATFIND procedure for empirically deriving the Assessment Subtest (AT; that is, a subtest composed of items that…

Examinee effort can impact the validity of scores on higher education assessments. Many studies of examinee effort have briefly noted gender differences, but gender differences in test-taking effort have not been a primary focus of research. This review of the literature brings together gender-related findings regarding three measures of examinee…

Educational program assessment studies often use data from low-stakes tests to provide evidence of program quality. The validity of scores from such tests, however, is potentially threatened by examinee noneffort. This study investigated the extent to which one type of noneffort--rapid-guessing behavior--distorted the results from three types of…

This investigation examined whether different rates of rapid guessing between groups could lead to detectable levels of differential item functioning (DIF) in situations where the item parameters were the same for both groups. Two simulation studies were designed to explore this possibility. The groups in Study 1 were simulated to reflect…

Attali (2005) recently demonstrated that Cronbach's coefficient [alpha] estimate of reliability for number-right multiple-choice tests will tend to be deflated by speededness, rather than inflated as is commonly believed and taught. Although the methods, findings, and conclusions of Attali (2005) are correct, his article may inadvertently invite a…

Two software packages commonly used for multidimensional item response theory (IRT) models require the user to input values for the lower asymptotes of the item response functions. One way of selecting these values is to estimate lower asymptotes with a one-dimensional IRT model and use those estimates as fixed values in the multidimensional…

A series of 8 tests was administered to university students over 4 weeks for program assessment purposes. The stakes of these tests were low for students; they received course points based on test completion, not test performance. Tests were administered in a counterbalanced order across 2 administrations. Response time effort, a measure of the…

The validity of inferences based on achievement test scores is dependent on the amount of effort that examinees put forth while taking the test. With low-stakes tests, for which this problem is particularly prevalent, there is a consequent need for psychometric models that can take into account differing levels of examinee effort. This article…

The validity of inferences based on achievement test scores is dependent on the amount of effort that examinees put forth while taking the test. With low-stakes tests, for which this problem is particularly prevalent, there is a consequent need for psychometric models that can take into account different levels of examinee effort. This article…