Keith Johnson, Deseret News
Crime scene tape marks an area in Salt Lake City at the scene of a fatal stabbing in October 2009. New research shows undocumented immigrants account for only a small percentage of violent crimes committed in Utah.

SALT LAKE CITY — Contrary to majority public opinion, undocumented immigrants account for only a small percentage of violent crimes committed in Utah, researchers said at a Sutherland Institute forum Friday.

According to a Dan Jones & Associates Poll 62 percent of Utahans "definitely agree" or "probably agree" that illegal immigrants commit a disproportionate amount of crime. In reality, only about 5 percent of criminals in Utah jails are undocumented immigrants, said Charlie Morgan, an associate professor of social science at Brigham Young University.

"Our jails are not being overrun by undocumented immigrants," he said.

Twelve percent of convicted murderers and 8 percent of sex offenders at the state prison are undocumented immigrants. Morgan argued, though, that the numbers are inflated because undocumented immigrants can't apply for parole and are not eligible for rehabilitation programs that could qualify them for early release.

The majority of undocumented immigrants in Utah jails are being detained solely for border-crossing violations, Morgan said.

"They have not committed a crime other than they don't have papers," he said. "Technically, coming across the border is a civil offense — something you can't be put in jail for."

In general, children and grandchildren of immigrants commit more crimes than their progenitors, Morgan said.

Pam Perlich, a demographer for the University of Utah, attributed the trend to "assimilation."

"You see the same thing when you look at health data," she said. "They start eating French fries and watching TV. They get a lot less healthy and a lot more American."

American society has long depended on immigration, Perlich said.

"They are us and we are them," she said. "We're all immigrants."

The country's attitude about immigration changes with the economy.

"When we have economic booms, we welcome people," Perlich said. "We need them. We want them."

But when unemployment is high, she said, "we want to blame things on the easiest target."

Data indicate, however, that immigrants contribute to the productivity of the nation. Because immigrants tend to work for less, they have lowered the cost of production, Perlich said. That, in turn, has raised the standard of living for the middle class.

"They absolutely do not cause unemployment," she said.

The Sutherland Institute is a Utah-based public policy research organization that supports limited government, private property rights and personal responsibility.