When re-testing a student with CogAT using the same test form and test level, we recommend at least a 3-month interval, preferably 6 months, to mitigate practice effects. Some options for retesting sooner include switching forms (from 7 to 8, or vice versa) or using the same test form and switching test levels.
Due to the test design and vertical scaling of the assessment, students can be tested up or down one level with validity and fairness. Student performance on each level of the assessment—whether "on-grade" or "off-grade"—is evaluated based on the expectations for a student that age and grade. That is, younger students taking a higher level of the test need to get fewer items correct than an "on-level" student. Older students taking a lower level of the test need to get more items correct than they would on their respective on-grade level test to obtain the same score.
When testing a student you expect is particularly high in ability, you might make the decision to go up a level so that the assessment feels more challenging and engaging to the student, although one level or one level down is appropriate to provide valid scores for that student. Additionally, the test has sufficient difficulty and ceiling so that a student taking a lower level can still score high enough to qualify for GT identification, and his/her scores are comparable to their peers who took the on-level test.
One area of careful consideration is switching students between Levels 8 and 9, because the item formats change from picture-based (Level 8) to word- and number-based. However, the assessment is scaled and normed so that scores articulate from level-to-level. In particular, caution is advised when switching from Level 8 to Level 9 for an English-learner, due to the format of the Verbal section at Level 9 and above.
