] What does it mean to have a high IQ? Well the first question to ask is “high IQ relative to whom?” Let us provide some background: relatives of modern-day IQ tests have been around since the late 1890s. The millions of test observations have enabled mathematicians and statisticians to establish several important characteristics about IQ scores. Namely, across a population, IQs follow a normal distribution which means that the same proportion of people will score higher than the average IQ score (usually set to 100), as the proportion of people scoring below the average score. In other words, 50% of the population have an IQ which is greater than 100, while the other 50% have an IQ lower than 100. To be able to get a complete picture of the statistical properties of IQ however, you also need to know the standard deviation of the test that is being employed to measure the IQ score. The standard deviation measures the dispersion around the mean of all the test observations (scores) in your sample, or for the population. Most IQ tests have a standard deviation of either 15 or 16 (some tests such as Cattell have a standard deviation of 24).