Since modern homelessness began more than thirty years ago, research and experience have overwhelmingly shown that investments in permanent housing are extraordinarily effective in reducing homelessness — as well as being cost-effective. Many of the most successful housing-based policies designed to address the homelessness crisis — in particular, permanent supportive housing for individuals living with disabilities and other special needs — were pioneered in New York City and have been replicated throughout the country. Numerous research studies have consistently confirmed that long-term housing assistance not only successfully reduces homelessness — it is also less expensive than shelter and other institutional care. Proven housing-based policies include: Federal housing assistance: Federal housing programs are one of the most successful housing-based solutions to reduce homelessness. The two largest federal housing programs are public housing and federal housing vouchers, known as Housing Choice Vouchers or Section 8 vouchers. Housing vouchers allow low-income households to rent modest market-rate housing of their choice and provide a flexible subsidy that adjusts with the family’s income over time. Studies show that public housing and federal housing vouchers are highly successful at reducing family homelessness and in ensuring that these families remain stably housed out of the shelter system. Permanent supportive housing: Pioneered in New York City in the 1980s, permanent supportive housing has now proven to be a successful and cost-effective solution to the homelessness crisis. The supportive housing model combines affordable housing assistance with vital support services for individuals living with mental illness, HIV/AIDS or other serious health problems. Moreover, numerous research studies have shown that permanent supportive housing costs less than other forms of emergency and institutional care. The landmark 1990 City-State “New York/New York Agreement,” which has been renewed twice, is the premier example of a permanent supportive housing initiative that successfully reduced homelessness in New York City and saved taxpayer dollars that would otherwise have been spent on costly shelters and hospitalizations. “Housing first”: Another proven solution developed in New York City and replicated nationwide is the “housing first” approach to street homelessness, which builds on the success of permanent supportive housing. The “housing first” approach involves moving long-term street homeless individuals — the majority of whom are living with mental illness, substance abuse disorders and other serious health problems — directly into subsidized housing and then linking them to support services, either on-site or in the community. Research studies have found that the majority of long-term street homeless people moved into “housing first” apartments remain stably housed and experience significant improvements in their health problems. Much like permanent supportive housing, the “housing first” approach is far less costly than emergency and institutional care, such as shelters, hospitals and correctional facilities. The fundamental cause of homelessness is the widening housing affordability gap. In New York City, that gap has widened significantly over the past decades, which have seen the loss of hundreds of thousands of units of affordable rental housing. At the same time that housing affordability has worsened, government at every level has cut back on already-inadequate housing assistance for low-income people and has reduced investments in building and preserving affordable housing. Finally, the weakening of rent regulation laws, which help keep around half of all rental apartments in New York City affordable, has accelerated the loss of low-cost housing. To address New York City’s wide housing affordability gap, the Federal, State and City governments must significantly increase investments in affordable rental housing, with a significant portion targeted to homeless families and individuals. Similarly, strengthening rent regulation laws would preserve affordable housing and protect tenants, allowing them to keep their homes.