It's so troubling to see a statistic misused like this. The vacancy rate includes all 'frictional' vacancies, such as the period between someone moving out of a

It's so troubling to see a statistic misused like this. The vacancy rate includes all 'frictional' vacancies, such as the period between someone moving out of an apartment and the owner finding a new tenant, or the period between a new unit being built and a tenant moving in. Because of this, though the vacancy rate can be stable, it's not the same units that are vacant from month to month, and in fact, San Francisco's vacancy rate is extremely low compared to less problematic housing markets.