There are many reasons he might have performed differently on the two tests, but the most important one is probably the change in test format from kindergarten/first grade to second grade and up. K/1 is in picture format (requires no reading), while second and up uses words and numbers, as well as pictures. (samples here:)

http://www.hmhco.com/hmh-assessments/ability/cogat-7/content2

Short answer: it's not the same test.

Last edited by aeh; 02/02/16 08:15 PM.
...pronounced like the long vowel and first letter of the alphabet...