Advances in Item Response Theory and Applications: An Introduction

Test theories can be divided roughly into two categories. The first is classical test theory, which back to Spearman’s conception of the observed test score as a composite of true and error components, which was introduced to psychologists at the beginning of this century. Important milestones in its and venerable tradition are Gulliksen’s Theory of Mental Tests (1950) and Lord and Novick’s Theories of Mental Test Scores (1968). second is item response theory, or latent trait theory, as it has been called until recently. At the time, item response theory (IRT) is having a major impact on the field of testing. Models derived IRT are being used to develop tests, to equate scores from nonparallel tests, to investigate item, and to report scores, as well as to address many other pressing measurement problems (see, e. g. , , 1983; Lord, 1980). IRT differs from classical test theory in that it assumes a different relation the test score to the variable measured by the test. Although there are parallels between models from and psychophysical models formulated around the turn of the century, only in the last 10 years has had any impact on psychometricians and test users. Work by Rasch (1980/1960), Fischer (1974), 9 (1968), ivrighi and Panchapakesan (1969), Bock (1972), and Lord (1974) has been especially in this turnabout; and Lazarsfeld’s pioneering work on latent structure analysis in sociology (Lazarsfeld, 1950; Lazarsfeld & Henry, 1968) has also provided impetus. objective of this introduction is to review the conceptual differences between classical test theory IRT. A second objective is to introduce the goals of this special issue on item response theory and seven papers. Some basic problems with classical test theory are reviewed in the next section. Then, approaches to educational and psychological measurement are presented and compared to classical theory. The final two sections present the goals for this special issue and an outline of the seven papers.