A recent study has put a dent in the claim that playing chess makes you smarter. In a study involving 3000 primary school students, pupils were given 30 hours of chess instruction to see if it improved there math results. It turns out there was no significant difference between the students who received chess lessons and those who did not.
However closer reading of the report on the study did throw up some interesting points. One is the observation that chess still helps develop existing ability, but does not bestow it. The second is that the majority of children enjoyed the experience.
Of course this is just one study, and other studies have produced different results, but it shows that further work in the area of chess, schools and achievement is required.