The Reliability of NWEA Results
The extensive item bank of questions used on the NWEA Measures of Academic Progress (MAP) tests have been developed over a substantial period of time. This has given staff charged with statistical analysis abundant opportunity to establish the reliability of the tests. The result has been the collection of a significant amount of reliability evidence over time.
Test and re-test studies have consistently yielded statistically valid correlations between multiple test events for the same student. Most such studies rely on the methodology of having students re-test within several days. NWEA test and re-test studies have typically looked at scores from the same students after a lapse of several months. Despite this methodology (which would have the expected result of lowering the correlation figures) the reliability indices have consistently been above what is considered statistically significant.
Internal reliability (reliability between test items) has also been impressive. This is all the more remarkable in view of the volume and breadth of the item bank, and the fact that MAP is an adaptive test. MAP users can be confident of the reliability of their tests. The rigor that has been applied to the reliability studies has left no doubt that the MAP assessment system has been constructed, and continues to be maintained, in a manner that assures more than adequate reliability. Additional information on MAP reliability and validity studies is available from the Research section of the NWEA web site.
Please note: on reports that contain summary information, by default NWEA will not display summary information for reporting groups of ten or fewer students. Summaries from such small data sets are not reliable and should not be used to make curriculum decisions for the student group.