that what they're seeing in those results is statistical rock-bottom. Rock-bottom is not ZERO families wanting to leave, it's what they've got now. The remainder are the people who have it so bad here that they can't see a difference between living in SF or Oakland or Vallejo or any other place with high poverty (so why relocate?).
This city is as vile a place to raise children as it has ever been. I also suggest that the improvement in % of families desiring to leave SF comes from a quantity of those families from the earlier survey actually doing so.
San Francisco hopes to reverse black flight
http://www.usatoday.com/news/nation/2007-08-26-urban-blacks_N.htm
Damn, man.....just damn.
I must assume you have good & sound reason. Whatever it is, by definition, must deserve honorable respect.