Browsing by Author "De Gruijter, Dato N. M."
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Item Comparison of the nonparametric Mokken Model and parametric IRT models using latent class analysis(1994) De Gruijter, Dato N. M.A nonparametric Mokken analysis of test data generally results in the rejection of different items as misfitting than an analysis with a parametric item response theory model. This is due to differences between the methods of analysis employed. Croon (1991) demonstrated that the assumption of "double monotony" of the nonparametric Mokken model can be tested with a latent class analysis using the EM procedure. This allows a comparison of the Mokken model of double monotony and parametric item response models within the same framework. The Mokken model was compared with parametric models using simulated data. It was demonstrated that latent class analysis provides a consistent comparison of item response models. Index terms: EM algorithm, item fit, item response theory, latent class analysis, model comparisons, Mokken model, Rasch model.Item Item-rest regressions, item response functions, and the relation between test forms(1991) De Gruijter, Dato N. M.; De Jong, John H. A. L.Levine (1982) used item-rest regressions for the estimation of item parameters, and this relationship was exploited in this research in the context of vertical equating. Results from a simulation and an empirical dataset were used to demonstrate that item-rest regressions were useful in verifying the relationship between two tests obtained from item parameter estimates. It is shown that in vertical equating designs the Rasch model cannot replicate the relationship between tests at the lower score levels when guessing is present. At higher score levels, however, the correct transformation function can be estimated, irrespective of the IRT model used. Index terms: equating, guessing parameter, item response functions, item-rest regression, Rasch model.Item On problems encountered using decision theory to set cutoff scores(1984) De Gruijter, Dato N. M.; Hambleton, Ronald K.In the decision-theoretic approach to determining a cutoff score, the cutoff score chosen is that which maximizes expected utility of pass/fail decisions. This approach is not without its problems. In this paper several of these problems are considered: inaccurate parameter estimates, choice of test model and consequences, choice of subpopulations, optimal cutoff scores on various occasions, and cutoff scores as targets. It is suggested that these problems will need to be overcome and/or understood more thoroughly before the full potential of the decision-theoretic approach can be realized in practice.Item Reply to van der Linden's "Thoughts on the use of decision theory to set cutoff scores"(1984) De Gruijter, Dato N. M.; Hambleton, Ronald K.Item Small N does not always justify Rasch model(1986) De Gruijter, Dato N. M.In many applications of item response theory, it is of little consequence whether the Rasch model or a more accurate, but more complicated item response model is used. With small sample sizes, it might be advantageous to employ the Rasch model. A clear counterexample is the case of optimal item selection under guessing.Item Standard errors of item parameter estimates in incomplete designs(1988) De Gruijter, Dato N. M.Lord and Wingersky (1985) derived the asymptotic variance-covariance matrix for item and person parameters in item response models, using maximum likelihood estimation. Their results can be used in incomplete designs, in which different test forms with common subtests are administered to different groups of examinees. It is also possible to estimate the accuracy of various designs beforehand, which enables the researcher to select the best of several designs under consideration. The possibilities are demonstrated for the one- and two-parameter models. Index terms: Asymptotic standard errors, Incomplete designs, Item banking, Information matrix, Maximum likelihood, Rasch model, Two-parameter logistic model.Item Test construction by means of linear programming(1990) De Gruijter, Dato N. M.The use of linear programming in the selection of test items entails setting a target information value for several ability levels, then constructing a test of minimum length that satisfies the constraints given by the target values. In the present paper the case of the uniform target is reconsidered. The dependency of item selection on item pool characteristics is demonstrated, and the relevance of uniform targets for test construction and the applicability of linear programming for test construction are discussed. Index terms: item response theory, item selection, linear programming, test length.Item Two simple models for rater effects.(1984) De Gruijter, Dato N. M.In many examinations, essays of different examinees are rated by different rater pairs. This paper discusses the estimation of rater effects for rating designs in which rater pairs overlap in a special way. Two models for rater effects are considered: the additive model and a nonlinear model. An illustration with empirical data is provided.Item The use of item statistics in the calibration of an item bank(1986) De Gruijter, Dato N. M.An IRT analysis based on p (proportion correct) and r (item-test correlation) is proposed for a group of tests having items in common. The procedure is a generalization of a procedure proposed by De Gruijter and Mooijaart (1983) which is related to procedures for the factor analysis of dichotomous data. The procedure results in IRT item parameters using data from examinee groups with subsets of common items; it is, therefore, particularly appropriate for calibrating items for use in small-scale item banks. Simulated data are used to illustrate the procedure.