I don't know if you guys know about how social sciences work, but the trick is to find correlations. For example, political affiliation and church attendance. Grades and IQ, family status, or income.
In education, among the highest correlation is ethnic group (I'm Hispanic, for full disclosure). If you look at the overall numbers in CA, education seems pretty bad, but if you divide by ethnicity, it's not. After all, Irvine is under the same state regulations as Watts and the teachers get paid about the same. The "decline" in CA education is almost all a demographic shift.