I am pretty sure the norms are in 3 month blocks, not month by month. So all kids are being measured against norms that are an approximate bracket, not to the month accurate.
That's my understanding too. I've also heard that for a reliable estimate of IQ it's best to wait until children are older - around 7 or 8. In my family's very *very* small statistical sampling, our one child who took the WPSII was tested at a very young 5, and her scores were an overestimate.
I'm also curious why a 3 year old was tested - it seems so young! Was it for school or was it part of an analysis for something else? Were you just curious?
Best wishes,
polarbear
