NEW RESEARCH: The impact of illegal aliens on crime rates, data codebook and “do file”

17 Jan , 2018  

The Crime Prevention Research Center is proud to reveal new research that analyzes unique newly released data on crime rates by illegal aliens.  Please download a copy: available here.

The data as a STATA file is available here.  See also the codebook and the “do file” (also a STATA file).

From the abstract:

Using newly released detailed data on all prisoners who entered the Arizona state prison from January 1985 through June 2017, we are able to separate non-U.S. citizens by whether they are illegal or legal residents. This data do not rely on self-reporting by criminals. Undocumented immigrants are at least 142% more likely to be convicted of a crime than other Arizonans. They also tend to commit more serious crimes and serve 10.5% longer sentences, more likely to be classified as dangerous, and 45% more likely to be gang members than U.S. citizens. Yet, there are several reasons that these numbers are likely to underestimate the share of crime committed by undocumented immigrants. There are dramatic differences between in the criminal histories of convicts who are U.S. citizens and undocumented immigrants.

Young convicts are especially likely to be undocumented immigrants. While undocumented immigrants from 15 to 35 years of age make up slightly over 2 percent of the Arizona population, they make up almost 8% of the prison population. Even after adjusting for the fact that young people commit crime at higher rates, young undocumented immigrants commit crime at twice the rate of young U.S. citizens. These undocumented immigrants also tend to commit more serious crimes.

If undocumented immigrants committed crime nationally as they do in Arizona, in 2016 they would have been responsible for over 1,000 more murders, 5,200 rapes, 8,900 robberies, 25,300 aggravated assaults, and 26,900 burglaries.

A copy of the study is available here.



21 Responses

  1. […] Read the entire article here- The Impact of Illegal aliens on Crime Rates […]

  2. Tom Campbell says:

    I hope this study entices other researchers to look into other states’ results. ?How many other states collect data similar to AZ’s? It is important to measure AZ against other parts, and, hopefully, the rest of the country.
    The significant extent of this kind of issue in AZ is not new. I just finished reading Samuel K Dolan’s “Cowboys and Gangsters,” which looks at law men and law breakers in TX, AZ, and NM in the early third of the 20th C. The concluding sentence? “Nothing has changed.”
    Important study and results.

  3. Bruce Clark says:

    The US government recently issued serious travel warnings because of crime levels in various Mexican states. It would be interesting to correlate, if possible, the crime statistics in AZ and other US places with where in Mexico the criminal illegal aliens come from. Arizona is not far from Sinaloa and Texas borders Tamaulipas, both Mexican states high on the travel warning list.

    • Will Downs says:

      Big buzzer sound! 4-5 of the most dangerous states in Mexico are nowhere near the border. You are grasping wildly!

  4. Mark Hampton says:

    This paper doesn’t once mention the most obvious and serious problem with comparing the prison population with the general population to draw inferences about immigrant crime rates:

    Undocumented immigrants would be far less likely to succeed in any criminal defense and far less likely to seek and receive parole.

    Interestingly, I suspect the opposite is true of documented immigrants, perhaps explaining at least part of their lower conviction incidence: they tend to have good access to networks of lawyers and defense attorneys as their process of becoming immigrants and maintaining legal status requires it.

    Because the author has not even acknowledged this confounding factor, let alone address it, this study is not worth serious consideration.

    • johnrlott says:

      Thanks, Mark. But as the paper notes, neither of these explanations explain the results.

      1) Parole was abolished in Arizona as of January 1, 1994. “The Arizona Legislature passed truth-in-sentencing laws in 1993. Laws 1993, Chapter 255, altered earned release mechanisms and abolished parole for offenses committed on or after January 1, 1994.” The results are even strengthened if you only examine the period after that date.

      2) There is another way of measuring the severity of crimes by undocumented immigrants and that is instead of looking at the number of days in prison, you look at the relative share of undocumented immigrants committing the most serious violent crimes. And again they are over-represented by that measure.

  5. Bob Schmidt says:

    From my experience in Illinois with both citizens, legal and illegal aliens, the vast majority of crime is never captured in police reports, let alone court records or prison records.

    Maybe 90% of murders are in the murder statistics. But at the other extreme, less than 5% of burglaries are in those statistics. Less than 20% of arsons are in arson statistics (my specialty).

    Statistics on court records cannot be extrapolated to the entire society without a lot of other substantiation.

  6. John Lacher says:

    I am involved with a Community Watch Program and the social media platform called, Nextdoor in Chico, California. 8 out of 10 subjects that are arrested for crimes are in the United States illegally from Mexico. We have seen an increase in illegals from Mexico and crimes committed by Mexican illegals. Gov. Jerry Brown and Lt. Gov Gavin Newsome have contributed greatly to illegal entry and crimes after making California a sanctuary state. Chico, California reports a homeless population of between 1500 and 3000 people. We have no idea how many of the Mexican illegals are part of the homeless population.

  7. RUTH says:

    I can tell you from personal experience living in Az. for 25 years that illegals are a curse on the state and the country . I cant ell yo the many crimes of people I know personally that had crimes committed against them by illegals . My son alone had his car stolen with all his possessions in it as he was moving , They found it later burned up in the desert ,mostly they take it mexico or a chop shop . Thousands of auto accidents where the illegals jump out of the car and leave it there . My son was at the ATM machine and 4 Mexicans jumped him and beat him seriously . My friends have had crimes against them . The Phoenix police Dept will tell you they dont even bother taking police reports anymore from accidents because the illegals use alias’s never using their real names. I had a neighbor that was cut with a knife across their arms stopped at a light while illegals stole his car . Mesa ,Az had a serial rapists for 8 months and when finally found he was an illegal. I could go on but I know what the crime is nobody or their research will ever convince Americans any different than living the nightmare . When speaking with my foster sons friend who was from Mexico said “we only come here to make fast money send it home and within a few years we can build a beautiful house in Mexico . We dont care about Americans or this country ” Even my foster son who came as a refugee from Nicaragua was disgusted by what his friend said . Thats what this country is dealing with on a 8. on the Richter Scale .

  8. Ron Willis says:

    Mark Hampton referred to “Undocumented immigrants” as the problem, where honest folks on vacation in the US, forgot their documents. He and others making excuses for them will never admit the problem is illegal aliens, coming into our country in an unlawful manner, committing serious violent crimes against not only lawful US citizens, but other illegal aliens as well. That latter category greatly under reported, and thus not reflected in studies. In my 37 year law enforcement career, I’ve encountered the problem time and again.

  9. Candice Baron says:

    No more DACA no more illegals No more ever Build that Wall

  10. Dennis Hannick says:

    They are not “illegal immigrants”, “undocumented immigrants”, or “immigrants” of any stripe. They are by U.S. law, “illegal aliens”. To name them “immigrants” is to confer on them a quasi-legal status that they have neither earned or deserve.

    • Mark says:

      Thank you for posting the truth, those that control the language control the issue, that’s why they use the terminology.

  11. bobby tyson says:

    Every other study including those using state and federal data says this is a biased report with cherry picked data. But that can be expected with anything to do with John Lott.

    • johnrlott says:

      Dear Bobby: How exactly is this cherry picking? This data from the Arizona prison system includes ALL prisoners over 32 years. It is all the data that is available from the Arizona system. Please explain exactly how this is cherry picking. My work always tries to use all the data available. What you don’t understand is how the other studies either rely on mixing illegal and legal aliens together or relying on them to accurately answer whether they are illegal and whether they have a criminal record.

    • James Reid Hahn says:

      So Bobby, what’s your answer to Lott’s rebuttal?? Or are you like rest of Gun Controller crowd who just make accusations with no real data references to back them up?

  12. big red says:

    The new guy in Washington made a big deal out of two separate murders recently because they were committed by illegal aliens! I wonder how many other murders were committed on those particular dates by legal aliens ??

    • June says:

      That was two murders that could have been prevented! We already have enough criminals. Why take more from another country? Guess it only matters when it personally affects you! Sick!

    • George Schmidt says:

      So, if one of your family members were killed by someone who shouldn’t have been here in the first place, you might feel differently. Those two were just two of thousands of murders that shouldn’t have happened at all. People who are here illegally have nothing, so have nothing to lose by committing crimes. Most get away with it several times before ever getting caught.

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