Maybe you're wondering whether this person has a political agenda. Maybe even an unconscious one. It's certainly a possibility that I wouldn't rule out.
If they ran the numbers and it turned out to be the opposite, would they tell us? Would that paper ever see the light of day?
Anyway, let's see what this paper says:
Going beyond existing research, we utilize data from the Texas Department of Public Safety, which checks and records the immigration status of all arrestees throughout the state.
OK, sounds like a good data source, assuming that the data is accurate.
We make use of uniquely comprehensive arrest data from the Texas Department of Public Safety to compare the criminality of undocumented immigrants to legal immigrants and native-born US citizens between 2012 and 2018. We find that undocumented immigrants have substantially lower crime rates than native-born citizens and legal immigrants across a range of felony offenses. Relative to undocumented immigrants, US-born citizens are over 2 times more likely to be arrested for violent crimes, 2.5 times more likely to be arrested for drug crimes, and over 4 times more likely to be arrested for property crimes. In addition, the proportion of arrests involving undocumented immigrants in Texas was relatively stable or decreasing over this period. The differences between US-born citizens and undocumented immigrants are robust to using alternative estimates of the broader undocumented population, alternate classifications of those counted as “undocumented” at arrest and substituting misdemeanors or convictions as measures of crime.
So, that's a pretty bold statement. The differences are so large (2 to 4 times) that even if their estimates of the undocumented population have some error to them, the conclusion is "robust".
FWIW, there's a perception in Japan that "foreigners" bring crime with them, but it isn't borne out by crime statistics. But when it does happen, it gets a lot of attention from the media. Especially if it's a member of the US military. I think most people want to be on their best behavior when they're in a foreign country though. At least that's what I try to do. I don't want to be someone who adds to the perception that foreigners cause problems. I want to be a counter-example to that stereotype.
Looking at Table 1, the crime rates are given per 100,000 persons. The populations are based on estimates.
Each of these questions represents remarkable gaps in our scientific and policy understanding of undocumented immigration. This dearth is largely due to data limitations. Calculating group-specific crime rates is straightforward: It is the number of arrests within a particular group divided by its population (expressed per 100,000). In the case of undocumented immigrants, however, for years we lacked reliable estimates for both the numerator and the denominator required for such calculations. Regarding the number of undocumented immigrants (the denominator), data quality has improved in recent years as the Center for Migration Studies and the Pew Research Center now produce annual state- and national-level estimates of the undocumented population, ranging from 10.5 to 10.7 million in 2017 (1, 7).* Data on undocumented criminality (the numerator), however, have actually gotten worse over time. Despite the increasing centrality of local police in immigration enforcement (9), information on immigration status is remarkably scarce in most crime databases. Among the most widely utilized crime data sources, neither the Uniform Crime Reports, the National Crime Victimization Survey, nor the National Incident-Based Reporting System record information about immigration status. In addition, California stopped reporting the number of noncitizens in their custody to the Bureau of Justice Statistics (BJS) in 2013 and in 2017 became a “sanctuary state” by limiting information sharing between local criminal justice officials and federal immigration authorities (10). In 2016, they along with Nevada, New Hampshire, North Dakota, and Oregon did not report information on citizenship in their prison populations, and the BJS speculates that other states “likely provided undercounts” (11, p. 13).
This article is a notable exception to this trend in that, after review for scientific merit, the Texas Department of Public Safety (DPS) granted our research team access to case processing information for all arrests recorded between 2012 and 2018. The DPS data are unique in that they fully cooperate with the Department of Homeland Security (DHS) to check and record the immigration status of all arrestees throughout the state, including their legal status (21). Using these data, we address the empirical shortcomings that have hampered prior work in this area by accomplishing three interrelated objectives.
So they couldn't have done this study in California because it's a sanctuary state and the police don't keep those kinds of statistics.
A fool thinks himself to be wise, but a wise man knows himself to be a fool.