For decades, sanctuary city advocates have pointed to a so-called “chilling effect” where they claim local law enforcement must not cooperate with the Immigration and Customs Enforcement (ICE) agency to ensure that illegal aliens feel safe to report crimes. New analysis debunks the claim.

In April, when Department of Homeland Security (DHS) Secretary Alejandro Mayorkas announced a policy to shield criminal illegal aliens from arrest by ICE agents at courthouses, he justified the decision as necessary because “expansion of civil immigration arrests at courthouses … had a chilling effect on individuals’ willingness to come to court or work cooperatively with law enforcement.”

The Center for Immigration Studies (CIS) reviewed the Department of Justice’s National Crime Victimization Survey (NCVS) data and found that sanctuary city policies do not boost crime reporting by illegal aliens and that no such suppression of crime reporting among illegal aliens exists in jurisdictions that cooperate with ICE agents.

CIS researchers reveal:

There is no evidence in the NCVS data that crimes against immigrants are reported to police at lower rates than crimes against the native-born, indicating that the routine, even active, cooperation between local law enforcement and federal immigration authorities that takes place in most jurisdictions does not suppress crime reporting by immigrants. [Emphasis added]

Specifically, the analysis found that 62 percent of all serious crimes against all immigrants, including naturalized American citizens and non-citizens, were reported to the police. Compare this to 53 percent of all serious crimes against native-born Americans being reported to the police.

Similarly, 52 percent of serious crimes against non-citizens were reported to the police — about statistically equal to the 53 percent crime reporting rate for native-born Americans. When it comes to serious violent crimes, all immigrants had a crime reporting rate of about 61 percent compared to 49 percent of native-born Americans.

(Center for Immigration Studies)

(Center for Immigration Studies)

(Center for Immigration Studies)

When it comes to women, immigrants have a much higher rate of reporting crimes than native-born Americans. While 65 percent of immigrant women reported serious violent crimes to the police, just 48 percent of native-born American women reported.

In more than 80 percent of all victimizations reported to the police were reported by the victim of the crime or by a member of the crime victim’s household, the analysis found, regardless of their being immigrants or native-born Americans.

“We find no evidence in the NCVS data to support the ‘chilling effect’ theory that immigrants are more reluctant to report crimes,” the analysis states.

Today, there are hundreds of sanctuary jurisdictions across the U.S., including entire states such as California, New York, Illinois, Washington, Oregon, New Jersey, and Massachusetts.

John Binder is a reporter for Breitbart News. Email him at jbinder@breitbart.com. Follow him on Twitter here.