The Normal Distribution
IQ scores are normalized so that 100 is the mean and 15 is one standard deviation. 68% of people score between 85 and 115 (within one SD of the mean). 95% score between 70 and 130 (within two SDs). 99.7% score between 55 and 145 (within three SDs). The distribution is symmetric around 100.
What Different Scores Mean
IQ 85–115 (average range): approximately 68% of the population. IQ 115–130 (above average): ~15% of the population. IQ 130+ (gifted): ~2.3% of the population, roughly 1 in 44. IQ 145+ (highly gifted): ~0.13%, roughly 1 in 741. IQ 160+: roughly 1 in 31,560. IQ 180+: statistically rare enough that population estimates are unreliable — fewer than 1 in several million.
What IQ Tests Measure
IQ tests measure general cognitive ability — particularly fluid intelligence (abstract reasoning, pattern recognition, working memory) and crystallized intelligence (vocabulary, factual knowledge, verbal reasoning). They are among the strongest predictors of academic achievement, job performance in complex occupations, and socioeconomic outcomes. The g factor (general intelligence) is one of psychology's most replicated findings.
What IQ Tests Don't Measure
IQ tests do not measure creativity, practical intelligence, emotional intelligence, domain-specific talent, or wisdom. High-IQ individuals do not systematically outperform lower-IQ individuals on creative achievement above approximately IQ 120. Many factors beyond IQ — motivation, conscientiousness, opportunity, social skills — determine real-world achievement.
Häufige Fragen
What is an average IQ score?
An average IQ score is 100 by definition — IQ tests are normalized so the mean is 100 and the standard deviation is 15. Approximately 68% of people score between 85 and 115 (one standard deviation either side of the mean).
How rare is an IQ of 130?
An IQ of 130 is at the 98th percentile — approximately 2.3% of the population, or roughly 1 in 44 people. IQ 145 is at the 99.87th percentile (about 1 in 741); IQ 160 is approximately 1 in 31,560. These figures assume a perfectly normal distribution, which is an approximation for very extreme scores.
Does IQ predict success in life?
IQ is one of the strongest predictors of academic achievement and job performance in cognitively demanding occupations. Meta-analyses show correlations of 0.4-0.6 between IQ and job performance. However, above roughly IQ 120, other factors (conscientiousness, motivation, interpersonal skills, opportunity) become more important for real-world achievement. IQ does not reliably predict creativity or wisdom.