As a young kid I scored ok for my age, very high for 2 years older. Now I don't think I'm better at simple pattern tests then my peers.Im sure it means something, but especially with kids I've seen wildly different scores for the same kids on different moments and different kind of tests.
Statistics might average that out, but I've also seen it uses often to use as a tool to decide where young kids go. It's not accurate enough.