The problem of youth gangs is no longer confined to large cities, and neither police nor communities have developed systematic ways of dealing with them, according to a federally funded study released yesterday.

In a survey of 60 police departments, the researchers found that 27 departments reported youth gang problems but that only nine of these were in cities of more than 500,000 population.

Two-thirds of the cities with gang problems were smaller than those communities.

Only four of the 27 departments had written policies for dealing with gangs, and only 10 had provided any gang control training to police officers.

The study, based on 1981 data, found no evidence that police departments have any valid or reliable way to measure effectiveness of gang control techniques they use.

Nowhere did researchers find systematic coordination of a community's full resources, including social services agencies, neighborhood groups, prosecutors, judges, probation and parole agencies and police.

The study, "Police Handling of Youth Gangs," was conducted by the American Justice Institute of Sacramento under a grant from the Justice Department's National Institute of Juvenile Justice and Delinquency Prevention.

The study confirmed that a relationship still exists between city size and youth gangs, with five of six cities of more than 1 million reporting they had such gangs.