Economists have long doubted the wisdom of rent control, with basic economic theory positing that it acts as a price ceiling that reduces housing supply and creates market inefficiencies. Arguments in favor of rent control tend to center on creating affordable housing for a city’s poorest tenants and protecting tenants against large rent increases that would force them to relocate. San Francisco’s rent control laws apply only to buildings constructed before June 13, 1979, with no income restrictions for occupants. A 2019 paper by economists Rebecca Diamond, Tim McQuade, and Franklin Qian used a 1994 change in San Francisco law that expanded rent control to smaller multifamily buildings to study how otherwise similar buildings arrived at different outcomes based on whether or not they were subject to rent control. The supply problems created by rent control may also be exacerbated by a negative spillover effect on new housing construction.