Salt Lake City police have redefined what they will consider to be gang-involved crime -- a move that coincides with research on three years worth of crime to determine how many gangsters are breaking the law.

The new definition is more liberal and likely to show a boost in gang activity.

"We're not looking at it as overstating gang problems," said Lt. Isaac Atencio. "We look at it as getting a clearer picture of gang problems."

Salt Lake City is in the midst of an analysis, led by Moises Prospero, University of Utah researcher and assistant professor of social work, to determine the extent of its gang problems and how to prevent gang crime and membership. Atencio said the new definition was needed to assist the analysis.

The new definition went into effect last week. But Atencio said the definition would be applied retroactively to the start of 2006 to determine how many gang members have committed violent crimes.

Scott Decker, a professor of criminology and criminal justice at Arizona State University, said there "is no right answer" on how to classify gang crimes. Some cities, such as Los Angeles, use Salt Lake City's new definition while others, like Chicago, use the old.

The motive-based definition can make it tougher to classify gang crimes because police need more information, Decker said.

'It's hard to establish a motive when you only have a victim, and you don't have a perpetrator," Decker said.

ncarlisle@sltrib.com