| Abstract: | The National Assessment of Educational Progress (NAEP) uses item response theory (IRT)–based scaling methods to summarize the information in complex data sets. Scale scores are presented as tools for illuminating patterns in the data and for exploiting regularities across patterns of responses to tasks requiring similar skills. In this way, the dominant features of the data are captured. Discussed are the necessity of global scores or more detailed subscores, the creation of developmental scales spanning different age levels, and the use of scale anchoring as a way of interpreting the scales. |
