The Concept of Efficiency in Item Analysis
Richard J. Hofmann · Educational and Psychological Measurement · 1975
In this paper a new item analysis index, e, is derived as a function of difficulty and discrimination to represent item efficiency. It is demonstrated algebraically that the maximum discriminating power of an item may be determined from its difficulty and then item efficiency is defined as the ratio of observed discrimination to maximum discrimination. The magnitude of the e-index will range from zero to unity and will provide additional information for item analyses.