The COGAT is harder because it's higher grade level. There are different elements of the COGAT that aren't necessarily tested in the NNAT. which is entirely picture-based. If your child progresses at the same rate as expected, they should score similarly. In terms of %, most of the wealthier schools have a cut-off of 99 percentile to be automatically considered for AAP. the % are normed nation ...
NNAT score for one of them was below the benchmark (109). WISC verbal subtest was very high (152) with PRI 131 and average working memory (107) and processing speed (100) (FSIQ=133). CogAT verbal was only 133 (V 133, Q 121, NV 114, C 126). Started therapy first and then meds for ADHD in late second grade.
The main difference is group test vs individual test. For this current 2nd grade batch, it is even worst because NNAT is computer base. So the 6 years old kid is on his own facing the computer to complete the test. If the kid has any attention issues, which my son has, it is really easy to zip through and not paying enough attention or focusing. Whereas for WISC test, the psychologist is ...
The NNAT is one test given to kids who are very young. As it turns out, my kid also has ADHD, and that made it even worse. Kids can and do prep it, and that makes the scores skew. A high CogAT, high GBRS and/or high WISC all mean a lot more. A low NNAT coupled with a strong GBRS and strong CogAT will be an admit.