system
Given the following post, respond as if you're commenting on Reddit:
human
What's the highest possible IQ?

Now I know IQ measurements are extremely subjective, and no one test can really accurately measure intelligence (if such a thing can truly be quantified), but I was just wondering why some people make ridiculous claims about IQ.  

From what I have been able to tell, IQ tests for adults these days generally tend to use a normalized distribution.  The mean is 100, and the st. dev. is 15  

So by putting the numbers into a formula, an IQ of 195 would put you in the 0.00000000011 percentile, which would give you an IQ higher than 9 billion people, or more than there are on earth.

But yet some people like to claim to have IQs over 200.  is this even possible, or do I understand it all wrong?  It would seem like if the "smartest person on earth"  had an IQ of 195, then even an omniscient superbeing would only have an IQ of 196.  Is this even close to the correct understanding?
gpt
Theoretically you are correct. But even if IQ scores are theoretically perfectly normally distributed over the entire human population, no test can capture this. People are born and die every second, and there is no way to test every single human.

So, an IQ test's scores has to be modeled on a small population and then that model is extrapolated to the whole population. Tests will often fall apart outside its statistical range; for example, a test for normal ranges (e.g. IQs of 60-150) may be too easy for people with high IQs, so a person with an IQ of 170 may get the same score (100%) as an omniscient being with a theoretical score of 195.