Contributing to a competency model for engineering thermodynamics, we investigate the empirical competency structure of our exams in an attempt to answer the question: Do we test the competencies we want to convey to our students? We demonstrate that thermodynamic modeling and mathematical solution emerge as significant dimensions of thermodynamic…

This research simulated responses of 75 subjects to 30 items under the Birnbaum model and attempted a fit to the data using the Rasch model. When item discriminations varied from a variance of .05 to .25, there was only a slight increase in lack of fit as the variances increased. (Author/CTM)

Tests are proposed for testing the conditional independence assumption without first specifying a parametric form for the nondecreasing item characteristic curves. In an example, the conditional independence hypothesis is rejected for all possible forms of monotone item characteristic curves. (Author/BW)

Describes a goodness-of-fit statistic that considers the imprecision with which ability is estimated and involves constructing item fit tables based on each examinee's posterior distribution of ability, given the likelihood of the response pattern and an assumed marginal ability distribution. Also describes a Monte Carlo resampling procedure to…

Coefficient alpha, the most commonly used estimate of internal consistency, is often considered a lower bound estimate of reliability, though the extent of its underestimation is not typically known. Many researchers are unaware that coefficient alpha is based on the essentially tau-equivalent measurement model. It is the violation of the…

This paper discusses various issues involved in using the Rasch Model with multiple-choice tests and questions the suitability of this model for multiple-choice items. Results of some past studies supporting the model are shown to be irrelevant. The effects of the model's misfit on test equating are demonstrated. (Author JAZ)

This study reports results of an investigation based on simulated data of the distributional properties of the item fit statistics that are commonly used in the Rasch model calibration programs as indices of the fit of responses to individual items to the measurement model. (SLD)

Real test data of unknown structure were analyzed using both a unidimensional and a multidimensional latent trait model in an attempt to determine the underlying components of the test. The models used were the three-parameter logistic model and a multidimensional extension of the two-parameter logistic model. The basic design for the analysis of…

Several special cases of the general Rasch model, varying in complexity, were investigated to determine whether they could successfully model realistic multidimensional item response data. Whether the parameters of the model could be readily interpreted was also investigated. The models investigated included: (1) the vector model; (2) the product…

In most item response theory models a particular mathematical form is assumed for all item characteristic curves, e.g., a logistic function. It could be desirable, however, to estimate the shape of the item characteristic curves without prior restrictive assumptions about its mathematical form. We have developed a practical method of estimating…

The Rasch model of test theory is described in general terms, compared with latent trait theory, and shown to have interesting applications for the measurement of affective as well as cognitive traits. Three assumption of the Rasch model are stated to support the conclusion that calibration of the items and tests is independent of the examinee…

Qualitative evidence for the operation of partial knowledge is given by two findings. First, performance when second and subsequent choices are made is above the chance level. Second, it is positively related to first choice performance. A number of theories incorporating partial knowledge are compared quantitatively. (Author/LMO)

To demonstrate that some methods used to assess item fit can be applied to assess person fit and vice versa, performance of a chi-squared item-fit statistic was compared with that of a likelihood-based person-fit statistic for examinees and items under Monte Carlo conditions. (SLD)

In a preceding research report, ONR/RR-82-1 (Information Loss Caused by Noise in Models for Dichotomous Items), observations were made on the effect of noise accommodated in different types of models on the dichotomous response level. In the present paper, focus is put upon the three-parameter logistic model, which is widely used among…

A study was undertaken to develop guidelines for the interpretation of the parameters of three multidimensional item response theory models and to determine the relationship between the parameters and traditional concepts of item difficulty and discrimination. The three models considered were multidimensional extensions of the one-, two-, and…