These are the two researches who found that the arts do not
necessarily raise test scores.....(a study done maybe two years ago?)
"There is, however, a very good reason to teach arts in schools, and
it's not the one that arts supporters tend to fall back on. In a
recent study of several art classes in Boston-area schools, we found
that arts programs teach a specific set of thinking skills rarely
addressed elsewhere in the curriculum - and that far from being
irrelevant in a test-driven education system, arts education is
becoming even more important as standardized tests like the MCAS exert
a narrowing influence over what schools teach."
There was an article a while back in New York Times. (enter their
names in Google - lots of stuff comes up).