Recent years have seen growing use of tests with mixed item formats, e.g., partly containing dichotomously scored items and partly consisting of polytomously scored items. A matching two test characteristic curves method (CCM) for placing these mixed format items on the same metric is described and evaluated in this paper under a common-item…

A general model for the homogeneous case of the continuous response is proposed. The model is an expansion and generalization of the one proposed by the author in 1974, in which the open response situation is dealt with. In this generalized model, the closed response situation is dealt with, and it includes the model for the open response…

A simulation study was performed to determine whether a group's average percent correct in a content domain could be accurately estimated for groups taking a single test form and not the entire domain of items. Six Item Response Theory (IRT)-based domain score estimation methods were evaluated, under conditions of few items per content area per…

Classically parallel, tau-equivalently parallel, and congenerically parallel models representing various degrees of part-test parallelism and their appropriateness for tests composed of multiple item formats are discussed. An appropriate reliability estimate for a test with multiple item formats is presented and illustrated. (SLD)

A simulation study was performed to determine whether a group's average percent correct in a content domain could be accurately estimated for groups taking a single test form and not the entire domain of items. Six Item Response Theory (IRT) -based domain score estimation methods were evaluated, under conditions of few items per content area per…

The first purpose of this study was to investigate the stability of two essential dimensionality measures across 10 random samples within a particular assessment item (AT1) selection. Other purposes were to investigate the discrepancy of the essential unidimensionality estimates for a test across different AT1 selections and sample sizes and to…

The influence of anchor length on the accuracy of test equating was studied using Tucker's linear method and two Item-Response-Theory (IRT) based methods, focusing on whether equating accuracy improved with more anchor items, whether the anchor effect depended on the equating method used, and the adequacy of the inclusion of the guessing parameter…

The basic equations of item response theory provide a foundation for inferring examinees' abilities and items' operating characteristics from observed responses. In practice, though, examinees will usually not have provided a response to every available item--for reasons that may or may not have been intended by the test administrator, and that…

Whether the presence of bidimensionality has any effect on the adaptive recalibration of test items was studied through live-data simulation of computer adaptive testing (CAT) forms. The source data were examinee responses to the 298 scored multiple choice items of a licensure examination in a health care profession. Three 75-item part-forms,…

Two alternatives to traditional item analysis and reliability estimation procedures are considered for determining the difficulty, discrimination, and reliability of optional items on essay and other tests. A computer program to compute these measures is described, and illustrations are given. (SLD)

The reliabilities of 2-, 3-, 4-, and 5-choice tests were compared through an incremental-option model on a test taken by 154 high school seniors. Creating the test forms incrementally more closely approximates actual test construction. The nonsignificant differences among the option choices support the three-option item. (SLD)

The feasibility of constructing test forms with practically equivalent cut scores using judges' estimates of item difficulty as target "statistical" specifications was investigated. Test forms with equivalent judgmental cut scores (based on judgments of item difficulty) were assembled using items from six operational forms of the…

This study provides information about the total and component scores of the Test of English as a Foreign Language (TOEFL). First, the study provides comparative global and component estimates of test-retest, alternate-form, and internal-consistency reliability, controlling for sources of measurement error inherent in the examinees and the testing…

The purpose of this study was to compare the reliabilities of two-, three-, four-, and five-choice tests using an incremental option paradigm. Test forms were created incrementally, a method approximating actual test construction procedures. Participants were 154 12th-grade students from the Portland (Oregon) area. A 45-item test with two options…

The purpose of this study was to investigate the effect of using multidimensional items in a computer adaptive test (CAT) setting which assumes a unidimensional item response theory (IRT) framework. Previous research has suggested that the composite of multidimensional abilities being estimated by a unidimensional IRT model is not constant…