Developing a Taxonomy of Item Model Types to Promote Assessment Engineering

An item model serves as an explicit representation of the variables in an assessment task. An item model includes the stem, options, and auxiliary information. The stem is the part of an item which formulates context, content, and/or the question the examinee is required to answer. The options contain the alternative answers with one correct option and one or more incorrect options or distractors. The auxiliary information includes any additional material, in either the stem or option, required to generate an item, including texts, images, tables, and/or diagrams. In this study, we first present a taxonomy for item model development where variables in the stem are crossed with variables in the options to create a matrix of possible item model types. We then provide examples of each stem-by-option combination. Finally, we develop a software engine and apply the software to each item model type to generate multiple instances for each model.