The article linked below from Just Facts Daily details how the data for the Liberal Left/Socialist claims that illegals commit fewer crimes than citizens is false and, fake.
One area where the Leftist BS is in error is confusing "Correlation" with "Causation". An example of that is:
"When investigating the cause of crime in New York City in the 80s, when they were trying to clean up the city, an academic found a strong correlation between the amount of serious crime committed and the amount of ice cream sold by street vendors! (Which is the cause and which is the effect?) Obviously, there was an unobserved variable causing both. Summers are when crime is the greatest and when the most ice cream is sold."
Another item is the deliberate management of data to make a groups desired outcome seem correct. An example given is:
"The Obama administration, in particular, refused to release the names of convicted immigrant sex offenders and hid other details about crimes committed by immigrants."
Another example why that mutt should be viewed as a seditious foreign bad actor.
Anyway, if you do get into a shouting match with a Liberal Democratic/Socialist, (there is no other way to speak with them) you will have real data to bolster your position....bu, we know that won't matter.