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…

A procedure for obtaining Rasch model estimates of item difficulty and of ability is detailed. The procedure approximates the optimal but difficult to obtain "unconditional" estimates. (JKS)

A common problem in practical educational research is that of perfect scores which result when latent trait models are used. A simple procedure for managing the perfect and zero response problem encountered in converting test scores into measures is presented. It allows the test user to chose among two or three reasonable finite representations of…

"Composition analysis" refers to the mathematics of how component measures combine to produce composite measures based on Bookstein's functions. Composition analysis is applied to the different ways group members might work together such that their individual measures can be combined mathematically to calculate an expected measure for…

Two procedures for Rasch, sample-free item calibration are reviewed and compared for accuracy. The theoretically ideal "conditional" procedure is impractical for more than fifteen items. The more practical but biased "unconditional" procedure is discussed in detail. (Author/JKS)

This handbook explains how to do Rasch measurement. The emphasis is on practice, but theoretical explanations are also provided. The Forward contains an introduction to the topic of Rasch measurement. Chapters 2, 4, 5, and 7 use a small problem to illustrate the application of Rasch measurement in detail, and methodological issues are considered…

Statements made in a previous article of this journal concerning the Rasch latent trait test model are questioned. Methods of estimation, necessary sample sizes, several formuli, and the general usefulness of the Rasch model are discussed. (JKS)

In three lectures, Benjamin D. Wright of the University of Chicago introduces the Rasch model and its basic concepts. The first lecture, March 30, 1994 discusses the model created by Georg Rasch, a Danish mathematician, which Dr. Wright initially saw as merely a way to make raw scores into measures. Eventually, the model developed into a…

This book discusses constructing variables and making measures. It begins by outlining the qualities a number must meet before it qualifies as a measure of something. The basis is the measurement philosophy of G. Rasch. The first requirement for making good measures is good raw material. To achieve the possibility of comparisons, the data must…

This videotape contains a series of presentations by Benjamin D. Wright of the University of Chicago about the Rasch model and measurement in testing. The first presentation is excerpts from a workshop held in 1974 for educators from the Portland (Oregon) Public Schools and the Oregon Department of Education. Dr. Wright's lectures were part of a…

The analysis of fit of data to a measurement model for graded responses is described. The model is an extension of Rasch's dichotomous model to formats which provide more than two levels of response to items. The model contains one parameter for each person and one parameter for each "step" in an item. A dichotomously-scored item…