Methodology:

Every year, ECHO, the Austin/Travis County Ending Community Homelessness Coalition, conducts a count of homeless individuals living in public spaces. The goal of the "Count" is to enumerate the total number of people living in the "streets" or places not meant for human habitation.

The sheer number of homeless people is clearly an important thing to learn from the count. However, since it takes a great deal of energy to organize and carry a count, organizers have added an interview component or "survey" to the street count. In the past, volunteers have interviewed every 10th person to create a simple random sample of the people counted. The surveys provide organizers important information about unsheltered homeless people.  

Visit HUD's count page for further information:  http://www.hudhre.info/pit/