There is no defined definition of homelessness, however, most federal programs define it as an individual who lacks a fixed and night-time residence. It also includes anyone that uses a public or private shelter to reside in. One reason it is so difficult to count the number of homeless people, is because they are out on the streets of doubled up in homes, staying away from shelters. Many homeless people did not graduate from high school, have not been married, or have addiction problems.