Okay, the average IQ is 100 irrespective of age. Below a certain age, somewhere around late-teens or early-twenties, IQ is determined by factoring in the subject's age to a comparison between their absolute score and the 'typical' score for different ages. Therefore, Fo3nix, somebody 10 years old scoring the average for a 12-year-old would be rated an IQ of 120. Above that age, which varies according to the tests used, the IQ is a comparison of the subjects score with the average for their social group. This grouping might be chosen to be national, racial, or whatever. Chainfire, a good IQ test would NOT have any ambiguity. If the subject is intelligent enough to fully underatnd the question then the answer would be clear and unambiguous. Doglady, a good well-designed and marked IQ test is capable of giving a very good indication of how well an individual is able to reason and understand the information they get from their environment. It is the best determination of absolute intelligence that can be made, even though it is a comparitive measurement. Each particular IQ test can only give meaningful results over a limited range, so it is usually necessary to use several tests to 'home in' on the correct figure. I was quite puzzled at first, Chainfire, by your claim of an IQ of 140 and the standard of English in your posting. Perhaps English isn't your first language ?