Score Scales

Abstract

As discussed briefly in Chapter 1, scaling is the process of associating numbers or other ordered indicators with the performance of examinees. These numbers and ordered indicators are intended to reflect increasing levels of achievement or ability. The process of scaling results in a score scale. The scores that are used to reflect examinee performance are referred to as scale scores. The term primary score scale is used here to describe the scale that is used to underly all psychometric operations. In testing programs that equate alternate forms, scores typically are reported on the primary score scale and equating is used to ensure that scores have the same meaning regardless of the test form taken. As suggested in Chapter 1, the primary score scale is typically developed for an initial form. Subsequently developed forms are equated to an earlier form and then linked to the primary score scale.