LOS ANGELES (AP) — Los Angeles spends $100 million a year to deal with homelessness — much of it on arrests and other police services — but its departments have no coordinated approach for dealing with the problem, according to a new study.

Without clear guidelines, departments instead tend to rely on ad hoc responses, according to the report released Thursday by City Administrative Officer Miguel Santana.

“There appears to be no consistent process across city departments for dealing with the homeless or with homeless encampments,” the study said. “Responses to homelessness by city departments are not designed to end homelessness by systematically connecting the homeless to assessment, services, and housing.”

There is a joint city and county authority that fields emergency response teams to deal with problems involving the homeless, Santa said, but it has only 19 people to cover the entire county.

The 21-page report estimated the costs of sanitation, police, medical, mental health and other services for dealing with the homeless population, which previous estimates have put at more than 20,000 and growing.

However, the study said it was not possible “to get a full measure of the costs” of homelessness.

Santana recommended that the city create a policy for ending homelessness, an office or department to handle efforts, and if necessary the hiring of outside consultants to track the policies and their results.

Some groups that work with the homeless said the report misses the central problem.

Mollie Lowery of Housing Works, a Hollywood-based homeless housing organization, told the Los Angeles Times (http://lat.ms/1CQEn6i ) that it takes her group up to eight months to find housing.

“We already know what the need is, and we’re not matching it with housing,” Lowery said. “Now we’re just finding new ways to track them.”

Santana told the Times that providing an overview of the homelessness problem is an important first step.

“It’s easy to point fingers at government,” he said. “Nobody wants formerly homeless people living next to them. But most people are not born on skid row; they come from somewhere. This involves all of us.”