The extent to which properties of the ability scale and the form of the latent trait distribution influence the estimated item parameters of item response theory (IRT) was investigated using real and simulated data. Simulated data included 5,000 ability values randomly drawn from the standard normal distribution. Real data included the results for…

A rating scale can be expressed as a chain of dichotomous items. The relationship between the dichotomies depends on the manner in which the rating scale is presented to the test taker. Three models for ordered scales are discussed. In the success model, which represents growth, the lowest or easiest category is presented first. If the test taker…

During the past 15 years, considerable attention has been given to a conspicuous longitudinal change in grading patterns in higher education. Commonly referred to as "grade inflation," the phenomenon has been perceived by some as seriously weakening the meaning of grades but by others as reflecting a positive tendency for students to…

Draws attention to an existing methodology for handling decision-making in a typical planning situation of interrelated alternatives and data deficiency, and describes several important extensions that have recently been made to it. (Oriel Press Limited, 32 Ridley Place, Newcastle upon Tyne, NE1 8LH, Great Britain, $7.00 yearly.) (Author)

Illustrated is the power of multidimensional scaling in reducing a complex set of proximity measures to a simple geometric picture that shows the relationship among data objects. Methods are discussed for determining the number of dimensions needed to represent a set. (Author/DEP)

Suggestions are provided for activities involving the construction of mathematical models to solve "real-life" problems. (SD)

Arguing that the teaching of stochastic processes should reflect the experience and reality of the student, the author urges concentration on fundamental ideas. The development of intuition should be encouraged, and to this end continuity in teaching and a spiralled curriculum are important. (SD)

Presents a method of solving decision problems in conditions of incomplete knowledge of the probabilities of the states of nature. It uses all available information in order to delimit the region of ignorance as closely as possible. (Author)

During the past several decades, a new class of measurement theory, called latent trait (or item response) theory, has become popular. Supporters contend that results obtained through the use of this theory prove vastly superior to classical measurement statistics. This paper investigates the use of the Rasch model, one of the more popular latent…

The problem of obtaining designs that result in the most precise parameter estimates is encountered in at least two situations where item response theory (IRT) models are used. In so-called two-stage testing procedures, certain designs that match difficulty levels of the test items with the ability of the examinees may be located. Such designs…

An overview of the state of the art in psychological research is presented, with an emphasis on the attention given to effect sizes. The acceptance of small effect sizes for biomedical research is contrasted with the rejection of similar effect sizes for psychological research. The Binomial Effect Size Display is used to depict the practical…