I've been wondering why Asians picked the San Gabriel Valley rather than the San Fernando Valley. If you live in one of them, it's easy to come up with a long list of rather trivial differences between them. But to the man from Mars (or even from Minneapolis), they would seem close to identical — except for all the Asians now in the SGV.
The first evidence of an Asian predilection for the San Gabriel Valley was the formation of a New Chinatown in Monterey Park, in the southeastern San Gabriel Valley in the early 1970s. So, perhaps the die was cast then and everything else just followed from path dependency.
Or maybe it had something to do with smog. The SFV had bad smog in the 1970s but the more inland SGV had terrible smog. Perhaps the Asians didn't care as much about smog, or perhaps they had it all figured out that the new emissions controls would largely fix the smog problem, driving up home values in the SGV relatively more than in naturally less smoggy areas.
But, I think I've got a better idea. From an Asian family's perspective, the main difference between the San Fernando Valley and the San Gabriel Valley was that the former is almost all part of Los Angeles and the latter is made up of numerous independent municipalities. Even more to the point, most of the San Ferndando Valley schools are run by the giant LAUSD. In contrast, the San Gabriel Valley is made up of small independent school districts. So, Asians can concentrate enough numbers in an obscure SGV suburb like Arcadia to dominate school policy. More homework! More AP classes! More gifted classes! School orchestra!
This year's senior class at Arcadia H.S., a public school that's about 70% Asian and 20% white, has 35 National Merit Semifinalists.
In contrast, Asians have no hope of getting enough numbers in LA to motivate the LAUSD into doing much of anything for them.
(Here's a detailed map of Los Angeles County with LA City in white.)