Presents an overview of Rasch measurement models that begins with a conceptualization of continuous experiences often captured as discrete observations. Discusses the mathematical properties of the Rasch family of models that allow the transformation of discrete deterministic counts into continuous probabilistic abstractions. Also discusses six of…

Reviews methods for handling missing data in a research study. Model-based methods, such as maximum likelihood using the EM algorithm and multiple imputation, hold more promise than ad hoc methods. Although model-based methods require more specialized computer programs and assumptions about the nature of missing data, these methods are appropriate…

Defines the scope and significance of the field of informetrics and relates it to the earlier fields of bibliometrics and scientometrics. Practical and theoretical aspects of informetrics are discussed, including the development of mathematical models and the derivation of measures; and a brief overview of articles in this issue is included. (15…

Chaos theory describes the way systems change over time. It proposes that systems governed by physical laws can undergo transitions to a highly irregular form of behavior and that although chaotic behavior appears random, it is governed by strict mathematical conditions. This paper applies chaos theory to administrative and organizational issues.…

A theory for storage and retrieval of associative information is presented. Items or events are represented as random vectors. Convolution is used as the storage operation, correlation as the retrieval operation. A distributed memory system is assumed. The theory applies to recognition and recall and covers both accuracy and latency. (Author/RD)

This paper provides a concise summary of 10 years of research into defining appropriate statistical models for estimating school and teacher effect on student learning and other important educational outcomes. It discusses criteria for judging models and presents the formulae for the two-stage, two-level student-school hierarchical linear modeling…

A review of the literature was made of the various procedures for sequencing instructional units in individualized instruction programs. Procedures for validating sequences of instructional units, or learning hierarchies, were found to fall into two general categories. One category included procedures based on coefficients of dependence, while the…

The available methods for analyzing and interpreting data with multivariate analysis of variance are reviewed, and guidelines for their use are presented. Causal models that underlie the various methods are presented to facilitate the use and understanding of the methods. (Author/PN)

Defines a fuzzy retrieval model as the basis for extending a weighted Boolean information retrieval system in which numeric query weights are replaced by linguistic descriptors that specify the degree of importance of the terms. A relevance classification process is described, and implementation and evaluation of the fuzzy retrieval model is…

An error in an essential equation within the article by Williams and Zimmerman is corrected, and the algebraic inequalities are translated into questions a researcher can ask about simple or residualized difference scores. Williams and Zimmerman acknowledge the error and note that main conclusions are not affected. (SLD)

Focuses on methods of generating and evaluating hypertext. Highlights include historical landmarks; nonlinearity; literary hypertext; models of hypertext; manual, automatic, and semi-automatic generation of hypertext; mathematical models for hypertext evaluation, including computing coverage and correlation; human factors in evaluation; and…

Recent empirical studies of actual research practice demonstrate that general linear models, such as regression, have become increasingly popular. The present paper explores issues related to the interpretation of regression results, with illustrations drawn from studies in the counseling psychology literature. The primary focus of this paper is…

Assuming conditional normality and independence, standard estimation and hypothesis testing procedures for regression coefficients are the same whether using fixed x values, random x values or mixed fixed and random values. Contrary to Sockloff's suggestion, polynomial regression is useful with either fixed or random models. (See EJ 142 050). (CP)

The current state of multidimensional scaling using the city-block metric is reviewed, with attention to (1) substantive and theoretical issues; (2) recent algorithmic developments and their implications for analysis; (3) isometries with other metrics; (4) links to graph-theoretic models; and (5) prospects for future development. (SLD)

Mathematical programing formulas are introduced as new approaches to solve the classification problem in discriminant analysis. The research literature is reviewed, and an illustration using a real-world classification problem is provided. Issues relevant to potential uses of these formulations are discussed. (TJH)