Thanks for the info Marie. Looks like 240 may be near the test ceiling for language usage based on the reading ceiling being around the 93% of 10th graders. That would make the burble less surprising.
http://www.nwea.org/support/details.aspx?content=532 For example, in reading, the RIT scale measures with relative accuracy up to about 245. This represents the 93rd percentile at grade 10, and the 95th percentile at grade 8. If a student scores above we know that student performed high but may not be able to accurately assess how high they performed.
