The accuracy of Kendall's chi square approximation (M. Kendall, 1962) to circular triad distributions was assessed by comparing estimated indices to enumerated values across upper and lower tails of cumulative proportions of circular triad distributions. In general, the approximation was found to be quite good, and its use is discussed. (SLD)

As examples of models that are not based on normality or its approximation, the logistic positive exponent family of models is discussed. These models include the item task complexity as the third parameter, which determines the single principle of ordering individuals on the ability scale. (SLD)

Discusses two forms of separability of item and person parameters in the context of response time models. The first is "separate sufficiency," and the second is "ranking independence." For each form a theorem stating sufficient conditions is proved. The two forms are shown to include several cases of models from psychometric…

For trinary partial credit items, the shape of the item information and item discrimination functions is examined in relation to the item parameters. Conditions under which these functions are unimodal and bimodal are discussed, and the locations and values of maxima are derived. Practical relevance of the results is discussed. (SLD)

Traditional and innovative uses of the Rasch model in the development and validation of both small- and large-scale psychological instruments are illustrated and discussed. Advantages of the model in maximizing scale interpretability and validity are presented. Both mathematical and conceptual explanations are provided using counseling psychology…

Provides a general mathematical framework is provided that can be specialized to four different reliability coefficients. Consideration of this general framework makes it easier to convey to students the individual character of the formulations of reliability and the extent of their underlying similarity. (SLD)

Hazard rate models are described, and selected techniques are used to analyze paired hazard rates when event times are right censored. The techniques are illustrated by looking at mortality patterns in husbands and wives. Recently developed measures and models are introduced. The advantages and disadvantages of the measures are discussed.…

Describes the Rasch measurement partial credit model, what it is, how it differs from other Rasch models, and when and how to use it. Also describes the calibration of instruments with increasingly complex items. Explains pivot anchoring and illustrates its use and describes the effect of pivot anchoring on step calibrations, item hierarchy, and…

This book is a compendium of recent item response theory (IRT) research that reviews 27 IRT models. The book contains a historical overview of IRT followed by six sections that deal with the application of a particular IRT model or set of models. (SLD)

Using higher order factor models, this article illustrates latent curve analysis for the purpose of modeling longitudinal change directly in a latent construct. Provides examples with simultaneous estimation of covariance and mean structures for a single-group and two-group structure. (SLD)

This article analyses mathematical modelling from several different perspectives and contrasts modelling with problem solving. Then it describes the ways in which modelling, applications, and problem solving are approached in several Latin American countries. It further describes workshops for secondary schools and for university teachers in which…

Hidden Markov models (HMMs) are widely used in bioinformatics, speech recognition and many other areas. This note presents HMMs via the framework of classical Markov chain models. A simple example is given to illustrate the model. An estimation method for the transition probabilities of the hidden states is also discussed.

This article describes a mathematical biology workshop given to secondary school teachers of the Danville area in Virginia, USA. The goal of the workshop was to enable teams of teachers with biology and mathematics expertise to incorporate lesson plans in mathematical modelling into the curriculum. The biological focus of the activities is the…

Cognitive performance is affected by an individual's characteristics and the environment, as well as by the nature of the task and the amount of practice at it. Mental performance tests range in complexity and include subjective estimates of mood, simple objective tests (reaction time), and measures of complex performance that require decisions to…

We investigate short-term learning from hints and feedback in a Web-based physics tutoring system. Both the skill of students and the difficulty and discrimination of items were determined by applying item response theory (IRT) to the first answers of students who are working on for-credit homework items in an introductory Newtonian physics…