This article organizes models for categorical item response data into three distinct classes. "Difference models" are appropriate for ordered responses, "divide-by-total" models for either ordered or nominal responses, and "left-side added" models for multiple-choice responses with guessing. Details of the taxonomy…

A computational model of the neural substrates of elementary associate learning is developed. It is used to demonstrate that several higher order features of classical conditioning could be elaborations of the known cellular mechanisms for simple associative learning. (Author/LMO)

The most familiar models of item response theory are defined at the level of individual subjects. It is possible, however, to define such models for groups of subjects. This paper discusses group-level item response models, their uses, and their relationships to subject-level models. (Author/JKS)

A structural equation model is proposed with a generalized measurement part, allowing for dichotomous and ordered categorical variables (indicators) in addition to continuous ones. A computationally feasible three-stage estimator is proposed for any combination of observed variable types. Two multiple-indicator modeling examples are given.…

Presents a general mathematical framework for information retrieval, in which query evaluation is seen as a mapping from the free term algebra built by query descriptors and weights to the semantic algebra of evaluation value. Competing mathematical models that try to describe how retrieval systems behave are reviewed. (Author/MBR)

A constrained quadratic spline is proposed as an estimator of the hazard function of a random variable. A maximum penalized likelihood procedure is used to fit the estimator to a sample of psychological response times. (Author/LMO)

Presents a procedure for calculating the compass direction and velocity of present plate motions at any geographical point of interest. Includes a table of the relative and geographic motion of the 11 largest plates and a flow chart for determining their present motion. Also offers suggestions for classroom instruction. (ML)

A method requiring minimal computational effort is presented for transforming ordered residuals for purposes of testing the correctness of a regression model. The method maintains the same logical ordering in the transformed residuals as that of the original residuals and is suitable for either correlated or uncorrelated data. (Author/BS)

The present article reviews the procedures that have been developed for measuring the reliability of human observers' judgments when making direct observations of behavior. These include the percentage of agreement, Cohen's Kappa, phi, and univariate and multivariate agreement measures that are based on quasi-equiprobability and quasi-independence…

Issues regarding tolerance and confidence intervals are discussed within the context of educational measurement, and conceptual distinctions are drawn between these two types of intervals. Points are raised about the advantages of tolerance intervals when the focus is on a particular observed score rather than a particular examinee. (Author/BW)

The Galois-lattice is a graphic method for representing all possible developmental phases to reach a given total knowledge via different partial knowledge structures. Algorithms are proposed for incorporating statistical analysis into the Galois-lattice method. A comparison to the Rasch model and application for educational research are given. (BS)

Presents a model for projecting community college enrollments, providing a rationale for and explanation of the use of the following variables: high school seniors in the district; total population in the district between the ages of 20 and 29, and 30 and 39; insured unemployment rate; and capping of enrollment by senior institutions. (DMM)

A latent class model for rating data is presented which provides an alternative to the latent trait approach of analyzing test data. It is the analog of Andrich's binomial Rasch model for Lazarsfeld's latent class analysis (LCA). Response probabilities for rating categories follow a binomial distribution and depend on class-specific item…

Structural equation models require formidable computational techniques. Testing the goodness of fit involves discrepancies between original correlations among variables and correlations estimated by solved path coefficients. A BASIC computer program which solves these problems is presented and discussed. (Author/GDC)

The approach of J. D. Sneed is used to argue for a distinction between theoretical and nontheoretical (or empirical) entities. Attention is directed toward this approach as an important facility for looking at statistics and for constructing a framework for the correct use of statistical theory in information retrieval experiments. (MBR)