Adapting the Index of Item-Objective Congruence to Items with Multiple Objectives

Abstract

Finding the content validity of a test is a crucial step in assuring its quality. Enlisting the help of a team of content specialists to rate each item on the test is the simplest and most effective way to do so. Rovinelli and Hambleton (1977) adapted a procedure proposed by Hemphill and Westie (1950) and adjusted the latter’s formula to compute the Index of Item-Objective Congruence (IIOC) which can be used for measuring content validity. This article explains the mathematical reasons behind the IIOC formula and simplifies its form so that the new form can be easily adapted to a test item with multiple objectives. In addition, this form can be used with any rating scale. Two extensions of the IIOC formula proposed by another team of authors are shown to be incompatible with each other and with the form derived in this article.