There is an increasing interest in reporting subscores, both at examinee level and at aggregate levels. However, it is important to ensure reasonable subscore performance in terms of high reliability and validity to minimize incorrect instructional and remediation decisions. This article employs a statistical measure based on classical test theory that is conceptually similar to the test reliability measure and can be used to determine when subscores have any added value over total scores. The usefulness of subscores is examined both at the level of the examinees and at the level of the institutions that the examinees belong to. The suggested approach is applied to two data sets from a basic skills test. The results provide little support in favor of reporting subscores for either examinees or institutions for the tests studied here.

The purpose of this ITEMS module is to provide an introduction to subscores. First, examples of subscores from an operational test are provided. Then, a review of methods that can be used to examine if subscores have adequate psychometric quality is provided. It is demonstrated, using results from operational and simulated data, that subscores have to be based on a sufficient number of items and have to be sufficiently distinct from each other to have adequate psychometric quality. It is also demonstrated that several operationally reported subscores do not have adequate psychometric quality. Recommendations are made for those interested in reporting subscores for educational tests.

Recently, there has been an increasing level of interest in reporting subscores for components of larger assessments. This paper examines the issue of reporting subscores at an aggregate level, especially at the level of institutions to which the examinees belong. A new statistical approach based on classical test theory is proposed to assess when subscores at the institutional level have any added value over the total scores. The methods are applied to two operational data sets. For the data under study, the observed results provide little support in favour of reporting subscores for either examinees or institutions.

Recently, there has been an increasing level of interest in reporting subscores. This paper examines the issue of reporting subscores at an aggregate level, especially at the level of institutions that the examinees belong to. A series of statistical analyses is suggested to determine when subscores at the institutional level have any added value over the total scores. The methods are applied to two operational data sets. For the data under study, the results provide little support in favor of reporting subscores for either examinees or institutions.

No abstract