The purpose of this study was to explore the degree of grain size of the attributes and the sample sizes that can support accurate parameter recovery with the General Diagnostic Model (GDM) for a large-scale international assessment. In this resampling study, bootstrap samples were obtained from the 2003 Grade 8 TIMSS in Mathematics at varying…

The Rasch model is an item analysis model with logistic item characteristic curves of equal slope, i.e. with constant item discriminating powers. The proposed goodness of fit test is based on a comparison between difficulties estimated from different scoregroups and over-all estimates. (Author)

This article demonstrates that the usual first-order factor model is inappropriate for analyzing the factor structure of creativity and intelligence tests. An alternative model that allows for the estimation of unique covariance between the fluency and originality scores is proposed. (Author/JAZ)

The purpose of this study is to present and illustrate the application of a general linear model for the analysis of test networks based on Rasch measurement models. Test networks can be used to vertically equate a set of tests which cover a wide range of difficulties. The criteria of coherence and consistency are proposed in order to assess the…

The first step of the data analysis with respect to the eventual application of the various new methods in latent trait theory is here initiated. The data are a set of approximately 500 item responses of each of 7,439 examinees to the Iowa Tests of Basic Skills, Form 6, on one of three difficulty levels, which correspond to the ages of 11, 12 and…

Rasch model equatings of multilevel achievement test data before and after the deletion of misfitting persons were compared. Rasch equatings were also compared with an equating obtained using the equipercentile method. No basis could be found in the results for choosing between the two Rasch equatings. (Author/LMO)

The purpose of this study was to compare the relative robustness of the one-, two-, and modified two-parameter latent trait logistic models for the Iowa Tests of Educational Development. Results suggest that the modified two-parameter model may provide the best representation of the data. (Author/BW)

Since all commonly used latent trait models assume a unidimensional test, the applicability of the procedure to obviously multidimensional tests is questionable. This paper presents the results of the application of latent trait, traditional, and factor analyses to a series of actual and hypothetical tests that vary in factoral complexity.…

A model developed by G. Rasch that assumes scores on some attainment tests can be realizations of a Poisson process is explained and expanded by assuming a prior distribution, with fixed but unknown parameters, for the subject parameters. How additional between-subject and within-subject factors can be incorporated is discussed. (SLD)

This study investigated the dimensionality of mathematics subscale scores from the National Assessment of Educational Progress for the assessment's Technical Review Panel, specifically for the data from the 1990 and 1992 main assessment in relation to students' instructional and noninstructional background variables. Discriminant analysis was…

Issues of concern to test developers interested in applying the Rasch model are discussed. The current state of the art, recommendations for use of the model, further needs, and controversies are described for the three stages of test construction: (1) definition of the content of the test and item writing; (2) item analysis; and (3) test…

Three test-analysis models were used to analyze three types of simulated test score data plus the results of eight achievement tests. Chi-square goodness-of-fit statistics were used to evaluate the appropriateness of the models to the four kinds of data. Data were generated to simulate the responses of 1,000 students to 36 pseudo-items by…

This study develops a weighted least squares method for transforming a logistic scale in such a way that the estimates of ability parameters on the tranformed scale are as comparable as possible with those on another scale. This scale tranformation process is referred to as equating of scales. Equating is an important procedure in studies…

This paper reports on a project which has developed the general latent class model as a framework for representation of item responses. This framework can be used to represent data in applications such as mastery tests and other kinds of achievement tests, where there is reason to believe that current foundations are deficient. Methods of…

Latent trait model calibration procedures were used on data obtained from a group testing program. The one-parameter model of Wright and Panchapakesan and the three-parameter logistic model of Wingersky, Wood, and Lord were selected for comparison. These models and their corresponding estimation procedures were compared, using actual and simulated…