Every morning I squeeze the orange juice two glassfuls one for Claire one for me. Oranges are very much themselves, each orange an individual in size, color, fragrance, softness. I can count oranges. How many shall I get out of the icebox to fill the two glasses? The trouble is that there is no constant number of oranges that makes a glassful. Sometimes it's only three. Other times it can take six. How on earth can I regularize this procedure?
Well, as I am sure you've already guessed, the solution is embarrassingly simple. The store sells oranges in 4 pound bags. No matter how many oranges it takes, the bag always weighs 4 pounds. Now "a pint's a pound the world around" and an orange is about half juice, by weight. By experiment and/or calculation I establish that 2 pounds of oranges make two glassfuls no more no less. This is always so, no matter how few or how many oranges it takes to weigh the 2 pounds.
The result of this abstract science is that I have a simple, fool-proof, infinitely reproducible, inferentially stable rule: "Take one 4 pound bag of oranges out of the icebox and squeeze half of whatever number of oranges happen to be in it." Two glassfuls are always produced - no matter how many or how few the oranges.
Weighing oranges is vastly superior to counting them perhaps not for art or even literature, but certainly for routinely obtaining a glassful of orange juice. But counting each orange is so immediate, so fulsome, so personal, so individually appreciative, so richly qualitative. While weighing bags of oranges is so impersonal, so meagerly singular, so general, so unappreciative of the true unique, individual nature of each orange, so niggardly quantitative. How dare I reduce the lovely, charming, richly multidimensional orange to a mere cold, stingy weight in lifeless, uncaring pounds what a travesty of nature!
But what a triumph for obtaining a glassful of orange juice every time. You might decry my reduction of the gorgeous orange to such a brutal simplicity as its weight. But you have to admit that for routinizing the production of glassfuls of orange juice you will never in a million years invent an approach that is as simple or as reliable. That's the difference between art and science, between counting right answers and constructing measures.
Measuring and counting. Wright BD. Rasch Measurement Transactions, 1994, 8:3 p.371
|Rasch Measurement Transactions (free, online)||Rasch Measurement research papers (free, online)||Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch||Applying the Rasch Model 3rd. Ed., Bond & Fox||Best Test Design, Wright & Stone|
|Rating Scale Analysis, Wright & Masters||Introduction to Rasch Measurement, E. Smith & R. Smith||Introduction to Many-Facet Rasch Measurement, Thomas Eckes||Invariant Measurement: Using Rasch Models in the Social, Behavioral, and Health Sciences, George Engelhard, Jr.||Statistical Analyses for Language Testers, Rita Green|
|Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar||Journal of Applied Measurement||Rasch models for measurement, David Andrich||Constructing Measures, Mark Wilson||Rasch Analysis in the Human Sciences, Boone, Stave, Yale|
|in Spanish:||Análisis de Rasch para todos, Agustín Tristán||Mediciones, Posicionamientos y Diagnósticos Competitivos, Juan Ramón Oreja Rodríguez|
|Forum||Rasch Measurement Forum to discuss any Rasch-related topic|
Go to Top of Page
Go to index of all Rasch Measurement Transactions
AERA members: Join the Rasch Measurement SIG and receive the printed version of RMT
Some back issues of RMT are available as bound volumes
Subscribe to Journal of Applied Measurement
Go to Institute for Objective Measurement Home Page. The Rasch Measurement SIG (AERA) thanks the Institute for Objective Measurement for inviting the publication of Rasch Measurement Transactions on the Institute's website, www.rasch.org.
|Coming Rasch-related Events|
|Jan. 21 - Feb. 18, 2022, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com|
|Feb. 2 - March 16, 2022, Wed.-Wed.||On-line course: Introduction to Rasch Analysis using RUMM (M. Horton, RUMM), Psychometric Laboratory for Health Sciences at the University of Leeds, UK|
|Feb. 28 - June 18, 2022, Mon.-Sat.||On-line course: Introduction to Classical and Rasch Measurement Theories (D. Andrich, I. Marais, RUMM), The Psychometric Laboratory at UWA, Australia|
|Feb. 28 - June 18, 2022, Mon.-Sat.||On-line course: Advanced Course in Rasch Measurement Theory (D. Andrich, I. Marais, RUMM), The Psychometric Laboratory at UWA, Australia|
|May 20 - June 17, 2022, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com|
|June 24 - July 22, 2022, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com|
|Aug. 12 - Sept. 9, 2022, Fri.-Fri.||On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com|
|Oct. 7 - Nov. 4, 2022, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com|
|June 23 - July 21, 2023, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com|
|Aug. 11 - Sept. 8, 2023, Fri.-Fri.||On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com|
The URL of this page is www.rasch.org/rmt/rmt83c.htm