Purpose of this paper is to provide an alternative formulation which allows for the model parameters to be determined given the structural specification of zero mean error and independence among errors for different items and between errors and true scores. (Authors)

A method based on homogeneity analysis (multiple correspondence analysis or multiple scaling) is proposed to reduce many categorical variables to one variable with "k" categories. The method is a generalization of the sum of squared distances cluster analysis problem to the case of mixed measurement level variables. (SLD)

This note shows that the formula suggested by N. D. Bryant and S. Gokhale (1972) for correcting indirectly restricted correlations when no information is available on the third (directly restricted) variable is accurate only in one special instance. A more general correction formula is illustrated. (SLD)

Current descriptions of results from hierarchical linear models (HLM) and hierarchical generalized linear models (HGLM), usually based only on interpretations of individual model parameters, are incomplete in the presence of statistically significant and practically important "slopes as outcomes" terms in the models. For complete description of…

A truncated version of the Cauchy distribution is introduced. Unlike the Cauchy distribution, this possesses finite moments of all orders and could therefore be a better model for certain practical situations. One such situation in finance is discussed. Explicit expressions for the moments of the truncated distribution are also derived.

The partial credit model (PCM) (G. N. Masters, 1982) can be viewed as a generalization of the Rasch model for dichotomous items to the case of polytomous items. In many cases, the PCM is too restrictive to fit the data. Several generalizations of the PCM have been proposed. In this paper, a generalization of the PCM (GPCM), a further…

Conditional observed score (COS) and latent trait (LT) definitions of differential item functioning (DIF) are explored to determine when they are equivalent. COS methods rely solely on observed measurements, and LT methods model the response to an item as a function of an unobserved hypothetical latent ability or trait. For the case of dichotomous…

The kappamax reliability index of domain-referenced tests is defined as the upper bound of kappa when all possibile cutoff scores are considered. Computational procedures for kappamax are described, as well as its approximation for long tests, based on Kuder-Richardson formula 21. The sampling error of kappamax, and the effects of test length and…

Confirms previously published research in concluding that specialty words tend to possess frequency distributions which cannot be described by a single Poisson distribution. (Author/PF)

In the traditional Guttman-Harris type image analysis, a transformation is applied to the data matrix such that each column of the transformed data matrix is the best least squares estimate of the corresponding column of the data matrix from the remaining columns. The model is scale free. However, it assumes (1) that the correlation matrix is…

Improvements of the Gaussian quadrature in conjunction with the Newton-Raphson iteration technique (TM 000 789) are discussed as effective methods of calculating the bivariate normal correlation coefficient. (CK)

Most articles on missing values assume the missing data are "missing at random" and ignore the process that "caused" the missing values. The condition under which this procedure is justified is explored here: the concept of missing at random is precisely defined, several examples are discussed, and two simple conditions are given which are…

The use of some very simple loss or utility functions in educational evaluation has recently been advocated by Gross and Su, Petersen and Novick, and Petersen. This paper demonstrates that more realistic utility functions can easily be used and may be preferable in some applications. (Author/CTM)

Develops a general revenue model that incorporates the feedback and interaction between major federal, state, and local revenue sources. The model is applied to California for the 1965-75 period and the results are applied to an analysis of the property tax limitation initiative. Available from Stanley J. Bowers, Executive Director, NTA-TIA, 21…