An individual is a known homeless if he has spent the night before the survey in an place which is unexpected for habitation (in that case, he is called homeless ), including night halts providing  a shelter ( warmth, coffee, etc. . ) but that are not equipped for sleeping, or in an housing service  (hotel or accommodation paid by an association, room or dormitory room in a collective accommodation hosting service,  places exceptionnally open in case of extremely cold weather).

Some people may not have their own housing and may be considered homeless as defined above : those who spent the night before the survey in a home, in a hospital, in a prison, in a squat, or those who have been hosted by an individual.

Ordinary housing is a housing defined by opposition to residence accommodation offering specific services (retirement homes, student residence, tourist residence, residence with social vocation, residence for persons with disabilities ... ).

Several categories of homeless people are not taken into account by the survey homeless 2012 :

• those who sleep in an unintended for housing place (the homeless) and who do use a meal distribution service or do not go to a place opened in the frame of the cold weather plan ;

• the homeless living in towns not provided with hosting services or meals distribution services or services open in the frame of the cold weather plan ;

• the homeless people living in towns with less than 20,000 inhabitants. However, 80 centers of 5 000 to 20 000 inhabitants were sampled using the method used for conurbations of more than 20,000 inhabitants ; these cities are in the scope of the pre-survey and the telephone survey of services, but not within the scope of the survey of individuals. The data collected in the telephone survey on these cities as well as the results of the INED survey will however enable to extrapolate the results of the survey of individuals in all conurbations of more than 5,000 inhabitants .

• non-French-speaking homeless people who speak languages not covered under the non-French-speaking questionnaire.