The problem with IQ tests is that they are subjective and can only measure what the individual already knows.
IQ is actually like a computer processor the faster the processor the more quickly the computer processes information.
The slower the processor the longer it takes.
Faster = smarter or high intelligence
Slower = dumber or average to low intelligence
My son had learning disabilities and was actually labeled as retarded the first time he was tested.
Today he is married and is the manager of the toy dept of our local Wal-Mart. He would never have achieved that if he were actually retarted.
Hence IQ is simply the speed at which the human brain processes information and uses it.