My DD9 took the SCAT in January. According to what they sent us, they do separate score comparisons for fall and spring, so your DD could take it at either time and be compared to students two grades above in the same season. From what I remember (not looking at our paperwork), it was strictly an above grade comparison. I don't recall seeing anything about her age or the ages of other test takers. They'll send a raw score, a scaled score and the percentile compared to fall or spring 4th graders (in the case of your DDin 2nd grade). The percentiles shift a bit each year depending on the students taking the test.
You may want to check with your school to see if they are familiar with SCAT. I tried to use DD's scores to advocate for acceleration but the school wouldn't accept them.
