The Use of Control Charts to Display Item Analysis Data

Abstract

A procedure is described in this paper for the display of item analysis data using two types of control charts. The item control chart consists of a plot of item difficulty versus each item with action and warning limits drawn to denote boundaries for the 95% and 99% confidence intervals. A reference line is drawn at a mean item difficulty of 50%. The second control chart consists of a plot of item discrimination versus item difficulty for all test items. This procedure provides for a more efficient display of test data and could be used to supplement computerized item-analysis programs.