so does education really raise iq or this just a trivial value from poorly designed study? for one thing, more intelligent people are less likely to be filtered and thus can stay longer in school. then there is the issue that iq increases with age till about 30 (years you should be finishing up with school) so doing a before and after study may either account for the effect of education or the effect of biological brain maturation. so a study would need to track two sets of people, before and after a few years, one staying in school while the other not. the only problem is there could be environmental effects that have nothing to do with stoodying as to why the educated group gets an increase in iq, like hazardous chemical exposure at work or home for the dropouts that keep their brains from developing fully. and lets say there is an increase in iq with education, when do the diminishing returns kick in?