Reviews previous investigations of how best to determine whether a user should continue to display output from an online retrieval system, and presents a model for providing the user with the estimated number of relevant records remaining in a retrieved set ranked by a retrieval status value. (40 references) (Author/CLB)

Reviews the growing literature on the forecasting of elections, providing an example in the form of 1988 congressional election predictions. Briefly discusses the history of election outcome prediction and outlines two scientific forecasting models which, the authors state, are appropriate for use in the classroom. (GEA)

Summarizes earlier research in the theory of information flow and its application to practical situations and to the relationship between information and the user's knowledge state. A model for creating information profiles is presented which mathematically represents changes in decision making effectiveness as a function of specific documents.…

The impact of misspecification on the estimation, testing, and improvement of structural equation models was assessed via a population study in which a prototypical latent variable model was misspecified. Results provide insights into the maximum likelihood estimator versus a limited two-stage least squares estimator in LISREL. (TJH)

To improve on cutoff scores based on absolute standards which may produce an unacceptable number of failures, a compromise is suggested. The compromise draws on the information in the observed score distribution to adjust the standard. Three compromise models developed by Hofstee, Beuk, and De Gruijter are compared. (Author/GDC)

Develops an approach for advance estimation of user charges based on information actually retrieved by searching numeric databases, and defines a method for query cardinality estimation. Based on the relational data model, which uses relational algebra, this method uses formal file descriptions to describe the database files. (LRW)

A model for division of fractions using money as manipulative material is presented. Eight levels are described, ranging from the development of language and concept introduction through types of problems to rule discovery and application. (MNS)

Current practice in structural modeling of variables is limited to means and covariances based on multivariate normality assumptions. This article extends structural equation models to higher order product moments and to non-normal distributions. Areas of possible research are described. (Author/JKS)

Tau, Lambda, and Kappa are measures developed for the analysis of discrete multivariate data of the type represented by stimulus response confusion matrices. The accuracy with which they may be estimated from small sample confusion matrices is investigated by Monte Carlo methods. (Author/LMO)

Conjunctive item response models are introduced such that: (1) sufficient statistics for latent traits are not necessarily additive in item scores; (2) items are not necessarily locally independent; and (3) existing compensatory (additive) item response models including the binomial, Rasch, logistic, and general locally independent model are…

The problem of managing the reserve of cobalt is presented, followed by a method for bringing the stockpiled amount from any level to a desired goal. Solving a stochastic programming problem is involved. The procedure is discussed in detail. (MNS)

A Bayesian procedure is developed for the estimation of parameters in the two-parameter logistic item response model. Joint modal estimates of the parameters are obtained and procedures for the specification of prior information are described. (Author/LMO)

Discusses the use of computer programs in science and mathematics. Provides examples of how computation offers a new means of describing and investigating scientific and mathematical systems and how computer simulation can be used to examine new kinds of models for natural phenomena. (JN)

A five by five covariance matrix representing longitudinal measurements at five occasions is used to illustrate that markedly different types of learning curves may generate indistinguishable covariance structures. An excellent fit of a simplex structure can be misleading. Common uses of covariance structure models for growth studies are…

Drawing on recently developed methodology for structural equation modeling with categorical data, this article proposes a new approach for investigating the behavior of dichotomously scored test items in relation to other relevant (observed) variables. A linear structural model relates the latent ability variable to a set of observed scores.…