The more recent score is probably the accurate one, unless you have some reason to believe he didn't do his best on the test. IQ testing is very unreliable in younger kids. Some will have inflated scores if they were exposed to lots of things at home (books, vocabulary, puzzles, educational toys, etc that other kids may not get) and others will have scores that are underestimates if they are in an unstimulating environment or they had developmental delays, a developmental disability, stranger anxiety, etc. Some kids simply develop faster than others. So the baby that walks at 8 months may not end up being the athlete in the long run. My DS has speech and motor delays due to being dyspraxic so it's really hard to get an accurate result on IQ tests even at age 6. As he matures his scores keep rising. I think a 140 on the WISC is around 99.5 percentile so one out of 200 people?
Hope this helps.
