If you search highly ranked high schools in the nation or just California alone, they are almost always costal, high tech industry concentrated, historically wealthy neighborhood where household income is very high and parents are very much involved and often being tiger moms/dads. Parents making more money know the importance of education/high scores so they push their kids, provide with all the tools, send them to extra classes, lessons, trainings, SAT classes, private tutors... By default, rich folks kids will do better and they do start early on when they are young.... It's not just Asians, Caucasians, brown Asians, all together...
So teachers often are just about same everywhere with very few exceptions. Yes, may be they are little better overall in Irvine than Compton but I wouldn't be surprised if the reverse is true...