'You can't be accurate': Annual count of US homeless population misses large numbers of people, experts warn

An ABC News analysis found that methods and resources vary from community to community, producing an inconsistent, piecemeal account.

Thousands of volunteers across the country spent a night in January canvassing their communities to look for people who may be experiencing homelessness, as part of the government's annual Point-in-Time count.

The count is required by the U.S. Department of Housing and Urban Development, and its results can be used alongside other factors to determine funding. But those estimates have often not been accurate, some experts told ABC News.

"We only have one day to get a snapshot of the homeless population," said Hannah Anderson with the YWCA, a Point-in-Time count organizer in Snohomish County, Washington. "You can't be accurate when you're counting people for one day."

An ABC News analysis found that methods and resources vary from community to community, producing an inconsistent, piecemeal account that even HUD acknowledges underestimates the number of unhoused people.

"The picture that HUD is getting, and that Congress is getting, and that the public is getting, isn't as clear as it could be and should be," said Eric Tars of the National Homelessness Law Center.