"Seventy-one percent (71%) of respondents reported they were living in San Francisco at the time they most recently became homeless, an increase from 61% in 2013. Of those, nearly half (49%) had lived in San Francisco for 10 years or more. Eleven percent (11%) had lived in San Francisco for less than one year. "
http://sfgov.org/lhcb/sites/default/files/2015%20San%20Franc...
So, no it's not "fast and loose," they actually did make a distinction between short- and long-term residents.