[csa]

It is relatively easy for a good IQ year to deliver a “false negative” — that is, a significantly lower score than a theoretical true score. This could be as simple as something like not sleeping well the night before or just simple ambivalence.

It is relatively difficult for a good IQ test to deliver a false positive — that is, a significantly higher score than a theoretical true score.

I personally don’t think that this issue is taken into consideration enough when discussing IQ.

[JoeAltmaier]

Right. My boys all achieved tests in grade school that varied from 100% to 3%. My wife worried that something was 'wrong' with them. I assured her by noting, its easy to not care about a test and get 3%. Its essentially impossible to accidentally get the 100% score