Detection of item degradation

Item degradation refers to a situation where an item’s initially favorable psychometric characteristics deteriorate over time. It may take the form of changes in item content relevance and representativeness (e.g., its relationship with the target latent construct), of deterioration in item technical characteristics (e.g., item means and discrimination), or of loss in the item’s utility (e.g., item-criterion relationship). This presentation discusses various statistical methods that can be used to study the presence, size, rate, and trend of item degradation. Throughout the presentation, in addition to discussing methodological, we will also use data from actual personnel selection tests to illustrate key points.