71% Of SF Homeless Once Had Homes In SF
http://sfist.com/2016/02/11/71_of_sf_homeless_once_had_homes_in.php
There's a lot to learn form the Homeless Point-In-Time Count & Survey Comprehensive Report of 2015, which is online in its entirety, but one detail to which Socketsite draws attention is the percent of the nearly 7,000 homeless San Franciscans who were once San Francisco residents with homes.
Specifically, that share has swollen to 71 percent, suggesting that much of San Francisco's homelessness epidemic is "homegrown," the product of factors within the city proper.
This figure runs counter to a popular theory that the city is so generous with its assistance money and programs that indigent people flock here from elsewhere, and that the majority of those on the street came from elsewhere.
Conducted by the nonprofit Applied Survey Research, the Point-in-Time count employs a "blitz" method, but it's basically just a head count of sheltered and unsheltered homeless that you can read about here.