Pub. date: 2009 | Online Pub. Date: October 05, 2009 | DOI: 10.4135/9780857020994 | Print ISBN: 9781412930918 | Online ISBN: 9780857020994| Publisher:SAGE Publications LtdAbout this handbook
Chapter 5: Classical Test Theory
James Algina & Randall D. Penfield
Classical test theory Psychological measurement is based on the responses of participants to stimuli that may have been presented by the psychologist or, when an observation study is done, may have occurred in a natural setting. In this chapter, we refer to process of obtaining the measurements as a test. Psychologists are well aware that, although responses to stimuli may reflect the processes she expected the stimuli to elicit, the responses often will also reflect processes she would have preferred not to elicit. Therefore individual differences in the observed measurements must be conceptualized as reflecting multiple sources of variance. A statistical theory of psychological measurement formalizes the idea that observed measurements reflect multiple sources of variance by using a statistical model for the observed measurements. Such models include the classical true score model (CTSM), extensions of the CTSM such as the parallel, tau-equivalent, and congeneric test models, the generalizability theory ...