In existing welfare service system housing services are mainly those categorized as staircase models. In these models individuals should graduate through a social rehabilitation process in order to earn their own housing.
The housing first principle suggests a paradigm shift to this usual approach. According to the principle, instead of being an ultimate goal housing is considered as a first step, a basis and a precondition for the start and for the success of the social recovery process.
The HF-principle has spread from the U.S. to Europe. Also in Finland some HF-services have been put into place in recent years. These units have successfully housed long-term homeless people with severe mental and substance abuse problems who have been living in streets for a long time in inhumane living conditions.
In the HF-model individual's housing is secured with supportive treatment services. The HF-model has evidence-based results from the U.S. which have proved that the model is effective especially in enhancing housing retention.