Constructing Instruments to Achieve Measurement

Abstract

During the item development stage, a pool of items are produced by experienced item writers according to the instrument specifications, which may include the number of the items to measure each aspect or content area and the format of each item. After items have been developed they are typically refined through a number of item trials. Instruments typically consist of item formats that require respondents to generate a response (constructed response item) and/or those that require respondents to choose a response from among alternatives (selected response item). Three basic types of selected response items are typically used in tests of proficiency: alternate choice, multiple-choice and matching items. Multiple-choice items consist of the correct response and a number of distractors. The item key is the correct response option for a multiple-choice item. Questionnaires often include selected response items with ordered response options. In order to achieve measurement, the number, order and wording of response categories need to be carefully considered. Raters or judges often rate persons according to one or multiple rating criteria on some performance.