(Drewbear's addition) Also note that essentially all mainstream IQ tests in use nowadays rate on several scales which address different functional areas such as working memory, processing speed and verbal comprehension. They do NOT test things such as personality or creativity, as these are much, much harder to quantify. IQ testing is also sensitive to environmental conditions like how the testee is feeling that day, what the weather is like (seriously. It influences mood and performance), and how recently the testee has had a similar test. It's perfectly common to see scores vary a bit, so someone could get a score of 101 one time and 98 another.