Multidimensional scaling (MDS) a highly reliable measurement technique, often requires an overwhelming task of the subject in the data collection procedure. This investigation was designed to determine the loss of precision in solution associated with five degrees of systematic reduction in the data collection task. Data were simulated via Monte…

An alternative item-selection procedure for use with Owen's Bayesian adaptive testing strategy is proposed. This procedure is, by design, faster than Owen's original procedure because it searches only part of the total item pool. Item selections are, however, identical for both methods. After a conceptual development of the rapid-search procedure,…

The major concern for any research model, whether disproportionate or not, is the research question and how well that question is reflected by the model. Three "exact solutions" for disproportional situations, the hierarchial, unadjusted main effects, and fitting constant methods, are discussed in terms of the research question that each…

The report describes the math model for an experimental ship handling trainer. The training task is that of a replenishment operation at sea. The model includes equations for ship dynamics of a destroyer, propeller-engine response times, ship separation, interaction effects between supply ship and destroyer, and outputs to a visual display system.…

The basic design for the national evaluation of the Follow Through program is presented, and some of the related issues of analysis are considered. The design, as it now stands, presents many difficulties for analysis. These analysis issues are seen to include the following: (1) What should be the unit of analysis?; (2) How is the effect of a…

The cohort survival model for projecting school district enrollments is presented for use in local district short-term planning. The basic model, modifications, and sample worksheets are presented. To assist in the calculations of local enrollment projections, step-by-step procedures frequently refer to the sample worksheets. Local administrators…

This paper analyzes some of the problems of using diffusion models to formulate marketing strategies for new products. Though future work in this area appears justified, many unresolved problems limit its application. There is no theory for adoption and diffusion processes; such a theory is outlined in this paper. The present models are too…

In this paper, a heuristic algorithm for constructing school timetables is described. The algorithm is based on an exact method that applies to a family of particular timetable problems. The procedure has been used to construct timetables for Swiss schools having about 50 classes, 80 teachers, and 35 weekly periods. Less than five percent of…

The document covers an operational entity-simulation system designed to permit observation and selective control of a military personnel system under a variety of policy alternatives. PERSYM is modularized to facilitate conversion to different military forces and the programing and inclusion of alternative policy logic modules. The system…

A study was made of the problem of representing the expectations of mean squares associated with analysis of variance sources of variation for experimental designs. These designs have a factorial structure over repeated measures or, for some other reason, have variates within a factorial design not all of which are mutually independent. A simple…

Three different strategies of choosing items for presentation in a simple list learning situation are compared. The instructional task was to teach the correct response to a number of stimulus items, using a paired-associate teaching procedure. Only one item could be presented on a given trial and the total number of trials was limited. The…

Multiple matrix sampling is a psychometric procedure in which a set of test items is subdivided randomly into subtests of items with each subtest administered to different subgroups of examinees selected at random from the examinee population. Although each examinee receives only a proportion of the complete set of items, the statistical model…

The question of whether a library's catalog should consist of cards arranged in a single alphabetical order (the "dictionary catalog) or be segregated as a separate file is discussed. Development is extended to encompass related problems involved in the creation of a book catalog. A model to study the effects of congestion at the catalog is…

To resolve a recent controversy between Klein and Cleary and Levy, a model for dichotomous congeneric items is presented which has mean errors of zero, dichotomous true scores that are uncorrelated with errors, and errors that are mutually uncorrelated. (Author)

Explicit formulas are derived for the asymptotic sampling variances and covariances of the maximum likelihood estimators for factor-analysis parameters in the special case where there is just one common factor. The effect of the number of variables on these variances and covariances is indicated. A formula is given showing to what extent the usual…