Notes & Quotes

"Isn't it astonishing that all these secrets have been preserved for so many years just so that we could discover them!"
Orville Wright in a 1903 letter about the invention of an efficient airplane propeller.

The Measurement of Time

Measurement is a creative dialogue between theory and reality. It profits from advances in both. Here are the insights of Ferdinand Gonseth, Professor of Higher Mathematics and Philosophy of Science, Swiss Federal Institute of Technology, Zurich, into the problem of constructing a clock, in "From the measurement of time to the method of research." In J. Zeman, Ed. (1971) "TIME in Science and Philosophy", Amsterdam: Elsevier.

"When one examines the needs to be met for measuring time with high accuracy, one is confronted with a certain number of difficulties of various orders, some of which are of a technical, or even technological nature, and others of a theoretical character. Still others may affect the very principle of scientific research and are, consequently, of a methodological nature. Seeing them thus clearly indicated, it may be thought that these different types of difficulties are independent of each other, and that in order to overcome them, it is necessary first of all to see to it that they are well separated. But this idea does not stand a closer analysis of what we will call, further on, the problem of high precisions. It appears on the contrary, that the difficulties to be overcome are interlinked, and that they must be approached as a whole." (p. 277)

"Of course, to a certain and possibly essential extent, the progress of clock-making technology has been inspired and oriented by a theoretical ideal, by the abstract model of the isochronic oscillator. The word abstract should mean here that it is a question of a model of a mathematical character, conceived according to the principles of so-called rational mechanics. The efforts of technicians and practitioners have long tended, and still tend, to realize this model as perfectly as possible, and as faithfully as the situation and technical means involved will permit. Most of the technical and industrial progress that took place up to the advent of electronic techniques could be analyzed and presented in this perspective: all research was oriented (or at least seemed to be oriented) towards the realization of conditions, which, in the ideal model, ensured the correct functioning of the isochronous oscillator. The improvements and discoveries to be made on the technical level seemed to answer the need for a guiding principle: that of seeking an ever greater approximation of the theoretical model." (p. 287)

This is the guiding principle that motivates the Rasch approach to psychological measurement!

Notes & Quotes … Rasch Measurement Transactions, 1991, 5:3

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
in Spanish: Análisis de Rasch para todos, Agustín Tristán Mediciones, Posicionamientos y Diagnósticos Competitivos, Juan Ramón Oreja Rodríguez

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