Five comparisons were made relative to the quality of estimates of ability parameters and item calibrations obtained from the one-parameter and three-parameter logistic models. The results indicate: (1) The three-parameter model fit the test data better in all cases than did the one-parameter model. For simulation data sets, multi-factor data were…

A study was conducted to compare the quality of the item parameter estimates obtained from the ANCILLES and LOGIST estimation procedures using goodness of fit as a criterion. Statistics used to compare the fit included a chi-square statistic and a mean square deviation statistic. Other analyses performed included comparisons of the distributions…

We concern ourselves with the hypothesis that two variables have a perfect disattenuated correlation, hence measure the same trait except for errors of measurement. This hypothesis is equivalent to saying, within the adopted model, that true scores of two psychological tests satisfy a linear relation. Statistical tests of this hypothesis are…

Two models of library circulation, the Markov model and the mixed Poisson Model, are applied to circulation statistics from the University of Saskatchewan. Goodness-of-fit tests indicate that neither model fits the data; in both cases, the set of noncirculating items is larger than that predicted by the model. (Author/LRW)

Focuses on the fact that an educational treatment typically involves an intervention in a growth process. By modelling this process, expected growth for various treatment groups under control conditions may be estimated. Actual growth can be compared with projected growth to estimate the value-added by the program. A simple model is developed. (RC)

Two models are presented to compare trainee and expert assessment strategies. The use of these procedures in assessment training programs is illustrated in a study of 5 postgraduate students in an environmental education course who were required to rate the work of 20 students. (SLD)

Discussion of operational effectiveness in libraries focuses on a modeling approach that was used to compare the effectiveness of a local interlibrary loan system with using a national system, the British Library Document Supply Centre (BLDSC). Cost figures and surveys of five academic libraries are described. (six references) (LRW)

A study involving 1,000 simulated examinees compared the partial credit and graded response models in computerized adaptive testing (CAT). The graded response model fit the data well and provided slightly more accurate ability estimates than those of the partial credit model. Benefits of polytomous model-based CATs are discussed. (SLD)

Effects of the following methods for linking metrics on detection of differential item functioning (DIF) were compared: (1) test characteristic curve method (TCC); (2) weighted mean and sigma method; and (3) minimum chi-square method. With large samples, results were essentially the same. With small samples, TCC was most accurate. (SLD)

Two methods of computing test equating coefficients under item response theory by the following authors are compared: (1) B. H. Loyd and H. D. Hoover (1980); and (2) M. L. Stocking and F. M. Lord (1983). Conditions under which the method of Stocking and Lord is preferable are described. (SLD)

To assess cross-observer agreement on personality profiles, an Index of Profile Agreement and an associated coefficient are proposed that take into account both the difference between the ratings and the extremes of their mean. Data from the Revised NEO Personality Inventory for 250 peer ratings/self-reports and 68 spouse ratings/self-reports…

Using one simulated and two real data sets, the effects of the systematic variation of the item-selection procedure and the stepsize method on the operating characteristics of computerized adaptive testing (CAT) for instruments with polychotomously scored rating scale items were studied. The six rating scale CAT procedures used performed well.…

The purpose of this paper is to link empirical Bayes methods with two specific topics in item response theory--item/subtest regression, and testing the goodness of fit of the Rasch model--under the assumptions of local independence and sufficiency. It is shown that item/subtest regression results in empirical Bayes estimates only if the Rasch…

A component analytic method for analyzing multivariate longitudinal data is presented that does not make strong assumptions about the structure of the data. Central to the method are the facts that components are derived as linear composites of the observed or manifest variables and that the components must provide an adequate representation of…