Imperialism and Measurement

"In Victorian Britain, the propagation of standards and values was the means through which physicists reckoned they could link their work with technical and economic projects elsewhere in their society. In an unprecedented manner, late Victorian scientists joined networks in which standard machines, values and practices were distributed worldwide: imperialism, mass production and metrology dominated their universe. They saw an immediate connection between imperial standards and the integrity of their laboratory work" (Schaffer, 1992, p.24).

The mainstream of quantification remains imperialist because it unthinkingly imposes unarticulated assumptions on all subjects and groups. Rating scale categories are assumed to correspond to equally spaced increments of the latent variable. A given raw score is assumed to mean the same, one thing no matter how it was obtained. Different groups and treatments are assumed part of a homogeneous whole.

Rasch practitioners, on the other hand, search for and identify conflicting performances and construct definitions among subjects or groups. Rasch methods build, as far as is possible, a post- imperial system based on shared expression, rather than imposed assumption. Individuals and groups manifesting different world- views are linked to the shared measurement system wherever they come into conjunction with it, but are not forced into it where they do not.

Since "the physical values which the laboratory fixes are sustained by the social values which the laboratory inculcates" (p. 23), the purpose of the May 1996 "Outcome Measurements in Rehabilitation" Conference is to strengthen the network through which our measurement standards and practices will be distributed. In a fragmenting world we need to establish a virtual metrology that fixes, at least temporarily, the agreement among those participating in the measurement effort as to the construct that is being measured and the relationships between measures on that construct. This metrology is virtual because the construct being measured is an idealized fiction, a figment of our imagination, a virtual reality that no one's data ever matches.

Schaffer S. (1992) Late Victorian metrology and its instrumentation. In R. Bud & S. Cozzens, Eds. Invisible Connections. Bellingham, WA: SPIE Press.

Imperialism and measurement. Fisher WP Jr. … Rasch Measurement Transactions, 1996, 9:4 p.463

Rasch Publications
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
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