A recent meta-analysis published in Psychological Science looks at how much education improves intelligence, and suggests that a year of school improves pupils’ IQ scores by between one and five points.
Ritchie and his colleagues looked at three particular types of quasi-experimental studies of educational effects on intelligence:
- Those estimating education-intelligence associations after controlling for earlier intelligence.
- Those using policy changes that result in individuals staying in schools for different lengths of time.
- Those using school-entry age cut-offs to compare children who are similar in age but who have different levels of schooling as a result of their specific birth dates.
Their meta-analysis comprised 142 effect sizes from 42 data sets involving over 600,000 participants.
- All three study designs showed consistent evidence that the length of time spent in school is associated with increased intelligence test scores (an average effect of +3.4 IQ points for one additional year of education).
- The third study design, age cut-off, had the largest effect size (+5.2 IQ points).
- The first study design showed the lowest effect (+1.2 IQ points).
- For policy change, the effect size was +1 IQ point.
The authors suggested that education seems to be the most consistent, robust, and durable way that has been identified for raising intelligence.