"The data are clear that sanctuary counties aren't crime-ridden hellholes," Wong said in an interview. The data only shows correlation; Wong says more research needs to be done to determine whether a causal effect is at work here. But he suspects that, by becoming a sanctuary area and refusing to involve local authorities in deportation matters, a city or county may actually make itself safer. If immigrants who came to the U.S. illegally fear working with police will lead to deportation, they're less likely to report crimes and assist with investigations.