The Implementation of Thurstone's and Guttman's Measurement Ideas in Rasch Analysis

Thurstone and Guttman have postulated a number of requirements for the measurement of opinions and attitudes around 40-60 years ago. They claimed that such a measure should consist of a defined origin and a unit of measurement that shares a linear continuum and is independent of the persons who are measured, similar to a yard stick which is used to measure height. Only when such requirements are met, can one tell by «how much» one is «more» or «less» than the other with respect to the trait or state that was measured. In this article the Rasch Probabilistic Analysis is introduced with its new terms. As a prominent method among the latenttrait methods, the Rasch Analysis is one which very elegantly addresses Thurstone's and Guttman's quest for sample-free measurement. Two examples, one pertaining to motives for running, and the other examining perceived exertion are introduced to illustrate the method's applicability to the domain of sport psychology.