Interesting. So they made a model that suggests there may be up to anywhere from 16-29 million, instead of the 11 million from the census data. There is always uncertainties with these models as the authors explain. Basing border apprehensions percentages on influx in particular involves a lot of guesswork. However, IF we assume that they are correct in their 22 million average, crime rates would be far lower for illegals than previously anticipated. They point this out:
"One of the most common arguments in favor of a tougher immigration policy is that undocumented immigrants are coming with a lot of criminality,” Kaplan notes. But paradoxically, the new findings may undercut that argument. He points out that previous studies, based on the widely accepted total of 11.3 million undocumented immigrants, found that the rate of serious crimes committed by these immigrants is lower than for U.S. citizens. The new findings suggest that the rate is even lower than previously believed: “You have the same number of crimes but now spread over twice as many people as was believed before, which right away means that the crime rate among undocumented immigrants is essentially half whatever was previously believed.”
They also agree with the census data that illegal immigration peaked over a decade ago and has been falling:
"There are key areas of agreement between this paper and the existing survey numbers. Both methods found that the greatest growth of the undocumented population happened in the 1990s and early 2000s. Both found that the population size has been relatively stable since 2008." (they have dropped)
So both agree that there are less illegal immigrants than before and either there are 11 million (half which are visa overstays) who commit less crime than native born Americans, or there are around 22 million, which mean they commit half of that crime.