Rasch SIG Lecture Series
How to convince your friends not to misuse raw scores
Ben Wright
Rasch SIG Primer Series
The graphical display of item characteristics
Randy Schumacker, Robert Mount, and George Marcoulides
Rasch Demo Worksheet
Mark H. Moulton
Abstract: This Excel file was developed to help students and practitioners of the Rasch Model get a simple and intuitive look at what goes on "under the hood" of most Rasch programs for dichotomous data.
The Excel workbook shows all the matrices, formulas, and iterations needed to understand how person abilities, item difficulties, standard errors, expected values, and misfit statistics are computed.
It also allows the user to perform simple experiments to see the effects of missing and misfitting data. You will find that, beneath the sophistication and apparent inscrutability of modern Rasch software, the model and its estimation algorithm are surprisingly easy to understand.
The workbook most closely emulates the UCON algorithm described by Wright and Stone in Best Test Design.
The spreadsheet is fully documented using Excel comments, which may be turned on and off as desired.
Course Syllabi
ED669_Psychometric Theory
Larry Ludlow, Boston College
Related Websites
The Institute for Objective Measurement
http://www.rasch.org
David Andrich's online course on Rasch Measurement