Starting from his first day as a candidate, President Donald Trump has made demonstrably false claims associating immigrants with criminality. As president, he has sought to justify restrictive immigration policies, such as increasing detentions and deportations and building a southern border wall, as public safety measures. 

He has also linked immigrants with crime through an Executive Order directing the Attorney General to establish a task force to assist in “developing strategies to reduce crime, including, in particular, illegal immigration, drug trafficking, and violent crime,” and by directing the Department of Homeland Security to create an office to assist and publicize victims of crimes committed by immigrants.

By surveying key research on immigration and crime, this report seeks to enable the public and policymakers to engage in a more meaningful policy debate rooted in facts. Immigrants’ impact on public safety is a well-examined field of study.

A rigorous body of research supports the following conclusions about the recent impact of immigrants in the United States:

• Immigrants commit crimes at lower rates than native-born citizens.
• Higher levels of immigration in recent decades may have contributed to the historic drop in crime rates
• Police chiefs believe that intensifying immigration law enforcement undermines public safety.
• Immigrants are under-represented in U.S. prisons.

Immigrants commit crimes at lower rates than native-born citizens

“Research dating back more than a century documents a pattern whereby the foreign-born are involved in crime at significantly lower rates than their peers,” note Bianca Bersani and Alex Piquero, a sociologist at the University of Massachusetts-Boston and a criminologist at the University of Texas, respectively.5) These scholars contribute to a vast body of research demonstrating that popular fears about immigration and crime have been unfounded.

Foreign-born individuals (“first-generation immigrants”) report lower rates of criminal offending than native-born citizens and they have less contact with the criminal justice system, as measured by arrest records. Indeed, two notable studies, highlighted in a report by the American Immigration Council, find:

• Foreign-born individuals are less likely than native-born individuals to have engaged in violent or non-violent antisocial behaviors in their lifetimes, including harassment, assault, and acquiring multiple traffic violations, “despite being more likely to have lower levels of income, less education, and reside in urban areas.” The study’s authors add that these findings hold for immigrants from major world regions including Africa, Asia, Europe, and Latin America. Their analysis drew on survey data from a nationally representative sample of over 40,000 U.S. residents aged 18 years and older.
• Foreign-born youth enrolled in U.S. middle and high schools in the mid-1990s had among the lowest delinquency rates when compared to their peers. These researchers focused on non-violent delinquent acts such as stealing, damaging property, or selling drugs. Their study drew on repeated surveys of over 20,000 adolescents conducted between 1994 through 2002.

When studies like these measure crime and related behavior based on self-reported accounts of behavior, they avoid biases caused by criminal justice enforcement decisions and policies. Importantly, Bersani and Piquero have shown that self-reported behavior can be reliably used to measure disparities in criminal behavior. Their comparison of self-reported crime data with official arrest records for 1,300 adolescents across seven years concluded that foreign-born individuals reported their arrests as accurately as their native-born counterparts. Therefore, “The finding that the foreign-born commit less crime than their U.S.-born peers is not a product of differences in reporting practices across these groups.”

In fact, the prevalence of foreign-born individuals among the Latino population helps to explain differences in violent crime rates between whites and Latinos. Harvard University sociologist Robert Sampson and colleagues have found that “the lower rate of violence among Mexican Americans compared with Whites was explained by a combination of married parents, living in a neighborhood with a high concentration of immigrants, and individual immigrant status.” Thus all else equal, ethnic/racial groups with a higher proportion of immigrants exhibit lower rates of crime.

Notably, integration into American society brings immigrants’ crime rates closer to the higher levels of native-born Americans, as shown in Figure 1. This occurs because the children of immigrants lose the cultural and social attributes that buffered their parents from criminal offending (as described in Part 2) and because some immigrant groups are constrained in socioeconomically disadvantaged communities.

Source: Bersani B. E. (2014). An Examination of First and Second Generation Immigrant Offending Trajectories. Justice Quarterly (31)2, 315–343.

To what extent does the lower crime rate of foreign-born individuals hold for those who are undocumented immigrants? Major national datasets lack information on respondents’ immigration legal status, and this information has not been systematically collected by law enforcement agencies or state departments of corrections. But a few studies using other data sources to differentiate by legal status have supported the conclusion that immigrants—regardless of legal status—do not have higher crime rates than native-born citizens. For example:

• A study comparing recidivism rates of individuals released from the Los Angeles County Jail in 2002 found no difference in the re-arrest rate of deportable and non-deportable immigrants.
  
• A study of recently booked adult arrestees in Maricopa County, Arizona in 2007 and 2008, found that: “In general, illegal immigrants and legal immigrants reported about one-half the [drug] use when compared to U.S. citizens.”
  
• An examination of 2010 Census data revealed that the groups who make up the bulk of the undocumented population—young, less-educated men born in Mexico, El Salvador, and Guatemala—have significantly lower incarceration rates than similarly situated native-born men.
  

In addition, as described in Part 2, the growth of the foreign-born population, including those who are undocumented, has coincided with a historic crime drop. Parts 2 and 3 show that communities that have implemented restrictive immigration policies have experienced little or no public safety benefit, while those which have embraced undocumented immigrants have sometimes outperformed the nationwide crime drop. Finally, as described in Part 4, data from federal courts—which reveal the legal status of sentenced immigrants—do not support a link between undocumented status and criminality.

Higher levels of immigration may have contributed to the historic drop in crime rates

The influx of immigrants in recent decades has coincided with a significant decline in reported crime rates, which may have been influenced by the growing immigrant population. Research has demonstrated that communities with larger immigrant populations have outpaced the public safety gains of their peers.

As shown in Figure 2, in 1990 the reported violent crime rate was 730 offenses per 100,000 residents. That same year the number of foreign-born individuals living in the United States was roughly 19.8 million (3.5 million of whom were undocumented). The violent crime rate began to fall in the mid-1990s and by 2014 it was half of its 1990 level, at 362 offenses per 100,000 residents. By that year, the foreign-born population had more than doubled, reaching 42.2 million people (including 11.1 million undocumented people).

Source: Brown, A. & Stepler, R. (2016). Statistical Portrait of the Foreign-Born Population in the United States. Pew Research Center, Hispanic Trends; FBI’s Crime in the United States series.

Source: Brown, A. & Stepler, R. (April, 2016). Statistical Portrait of the Foreign-Born Population in the United States. Pew Research Center, Hispanic Trends. Retrieved from statistical-portrait-of-the-foreign-born-population-in-the-united-states; U.S. Unauthorized Immigration Population Estimates. (November, 2016). Estimated Unauthorized Immigrant Population, by State, 2014. Pew Research Center, Hispanic Trends; United States Census Bureau. American Fact Finder.

Although not definitive in proving causation, these trends establish a critical fact about immigrants and public safety: crime rates have fallen to historic lows amidst the growth of the foreign-born population. As described next, studies examining the impact of immigrants on their adopted communities reveal that these communities have shared in and sometimes outpaced the nationwide crime drop.

Robert Adelman, a sociologist at the University at Buffalo, and his colleagues compared crime rates in 200 metropolitan areas with varying immigrant population sizes from 1970 to 2010. They found that cities with both large and small immigrant populations generally saw a decline in violent crime rates after 1990. Furthermore, the rate at which homicide declined was much greater in cities with larger immigrant populations than in cities with smaller immigrant populations. Property crimes also decreased faster in cities with larger immigrant populations than in cities with smaller immigrant populations. This result was echoed by Graham Ousey and Charis Kubrin, of the College of William and Mary and University of California-Irvine, respectively, in their review of homicide rates between 1980 and 2010 in 156 large cities. Similar findings led University of Alabama criminologist Lesley Williams Reid and colleagues to conclude “immigration does not increase crime rates, and some aspects of immigration lessen crime in metropolitan areas.”

Research has shown that crime rates have also decreased in “gateway” cities, which are the entry point cities to the United States and often the most densely immigrant-populated places. In addition, southwestern border states and cities were found to be safer than similarly sized non-border areas in 2010.

Even at the neighborhood level, communities with larger immigrant populations have lower crime rates. One study found that people living in Chicago neighborhoods in 2005 with at least 40% immigrants were 80% less likely to experience violence than people living in neighborhoods with no immigrants. In addition, immigration was generally found to not affect homicide rates of Latinos and to have mixed effects on the rate among African Americans, according to a study that looked at the relationship between immigration and homicide from 1985 to 1995 in Miami and San Diego, and from 1985 to 1994 in El Paso.

Researchers have suggested that immigrants help lower the crime rate in their communities because of their strong familial ties, their political participation, their orientation to the justice system, and their economic impact. Because foreign-born individuals disproportionately live in two-parent households, their families contribute to their community’s level of social cohesion and organization. By providing greater oversight in their communities, immigrant families and neighbors can improve public safety. Violent crime rates also decrease when immigrants see favorable political opportunities. As they gain political representation, immigrants become further encouraged to contribute to the civic life and collective organization in their neighborhoods. Furthermore, immigrant youth tend to be less cynical about the law and perceive greater social costs resulting from involvement in the justice system compared to the native-born population. Since criminal-justice contact may also jeopardize their immigration status, immigrants who willingly came to the United States for safety and better opportunities are more likely to be law-abiding than their U.S.-born counterparts.

Finally, the economic revitalization spurred by high immigration settlement in cities has also helped to reduce crime rates. As immigrants move into American communities, they increase economic activity and thus create jobs. This economic boost makes all residents less likely to engage in criminal activities.

Police Chiefs believe intensifying immigration law enforcement undermines public safety

Sanctuary cities—colloquially—are those jurisdictions that do not ask people about their citizenship status or do not detain undocumented individuals for federal immigration authorities beyond their release date. It is important to note there are multiple definitions of sanctuary cities because none are codified under federal law. Jurisdictions cannot impede Immigration and Customs Enforcement from gathering information on citizenship status on those that they have arrested, but some cities and local police have chosen to not fully enforce immigration laws. Some jurisdictions also choose not to detain those suspected of being undocumented following a 2014 federal court ruling that held immigration detainers were not sufficient reason to keep a person in local jail absent any other offense. According to President Trump, sanctuary cities “breed crime.” However, evidence refutes this claim, and major law enforcement groups and leaders have argued that intensifying immigration enforcement interferes with public safety goals.

Research on the impact of sanctuary city policies has shown that they do not have a negative impact on crime rates. Loren Collingwood, a political scientist at the University of California-Riverside, reviewed crime data for 55 jurisdictions before and after implementing such policies, and found no meaningful effect. Research published by the Center for American Progress found lower rates of crime in comparable jurisdictions that differ only on their sanctuary status.

Jurisdictions adopt sanctuary status in part to encourage undocumented immigrants to assist law enforcement investigations. Fear of the police (due to fear of deportation) would hamper such investigations. A poll of Latinos in Southwestern California, conducted by Lake Research Partners, supports that belief: 44% of Latinos surveyed said they would be less likely to report being a victim of a crime for fear the police would ask about their documented status. Oxford University sociologist David Kirk and his colleagues found that immigrants in New York City were much less likely to assist the police if they perceived the criminal justice system as being unfair to people like themselves.

Police groups and leaders defend sanctuary city practices for reasons that echo these research findings. To reduce crime, police in cities as different as Tulsa and Los Angeles have said they would rather work with immigrants instead of taking steps to deport them, including asking about citizenship status. That position has been endorsed by the Major Cities Chiefs Association and is also supported by a briefing memo from the International Association of Chiefs of Police. Law enforcement leaders have explained that engaging police in immigration enforcement work would deter crime reporting and cooperation. Rejecting President Trump’s criticism of sanctuary cities, Boston Police Commissioner William Evans has stated, “We need to build trust with the immigrant community.” He added: “The last thing we want is for people to be afraid of us … They won’t report crimes, or help us in their communities if they [are] afraid of us.”

Research revealing that aggressive immigration enforcement produces limited public safety benefit further supports the resistance of law enforcement leaders to intensified immigration law enforcement. Deportations and other tactics like the 287(g) policy (which allow local jurisdictions to enforce federal immigration statutes) have been used on immigrant communities to combat crime, but research shows that for the most part these methods were not effective in controlling crime. Northeastern University sociologist Jacob Stowell and colleagues’ analysis found that immigrant deportations did not reduce overall violent crime rates in metropolitan areas between 1994-2004, when controlling for other factors. The authors did find important regional variation: deportations lowered aggravated assault rates in border areas while increasing them in non-border areas. This suggested, they noted, that “the forced removal of individuals in non-border areas fractures the more delicate (i.e., less well established) information and resource networks, thereby undermining informal mechanisms of social control.”

Likewise, a study measuring the impact of the aggressive and well publicized 287(g) policy in Virginia’s Prince William County—which required police to check the immigration status of detainees whom they suspected to be undocumented in addition to screening jail inmates—revealed that the policy’s announcement led to a drop in aggravated assault rates, but not other types of crimes. As the authors note, it is unclear how much this outcome was attributable to changes in reporting.

Immigrants are Under-Represented in U.S. Prisons

Non-citizens currently make up six percent of the U.S. prison population while comprising seven percent of the total U.S. population. Non-citizens are therefore slightly underrepresented in U.S. prisons. Some immigration opponents have presented a partial picture of the federal prison system to suggest the opposite. As this section illustrates, non-citizens are increasingly over-represented in federal sentencing and incarceration due to a rise in prison sentences for immigration offenses.

Among the 1.5 million people imprisoned in state and federal prisons, 87% are held in state institutions. Within state prisons, four percent are non-citizens. Within federal prisons, however, 22% are non-citizens. According to the Bureau of Prisons, immigration law violations were the most serious offense for one-third of non-citizens serving federal prison sentences. As explained next through an examination of federal sentences, the increased use of imprisonment for immigration law violations is a major driver of the over-representation of non-citizens receiving federal sentences.

Note: State numbers are from December 2015 and federal numbers are from December 2016. States that did not not report citizenship data (Alaska, California, Nevada, and Oregon) are omitted.
Source: Carson, E. A. & Anderson, E. (2016). Prisoners in 2015. United States Department of Justice, Bureau of Justice Statistics; Federal Bureau of Prisons. (2017). Inmate Citizenship.

In the most recent years for which data are available, state courts imposed 1,132,290 felony sentences (in 2005) and federal courts imposed 71,003 sentences (in 2015). In 2015, 29% of federal sentences were for immigration offenses. It is important to note that the total number of federal immigration sentences has doubled between 2000 and 2015, increasing from 11,403 to 20,757, during a period in which sentences for other crimes increased by just seven percent. In its analysis of federal criminal cases in 2015, the Unites States Sentencing Commission noted that 82% of immigration cases involved “unlawful reentry into the United States or unlawfully remaining in the United States without authority” and another 12% involved transporting undocumented people across the border.

While non-U.S. citizens received a substantial share (42%) of all federal sentences in 2015, most of these sentences (66%) were for immigration law violations. Congressional proposals endorsed by the Trump administration would further increase penalties and create mandatory minimum sentences for illegal re-entry into the United States. If passed, the new sentences would significantly increase the number of non-citizens serving prison sentences for immigration offenses.

Note: Violent offenses were defined based on the United States Sentencing Commission’s Supplement to the 2015 Manual Guide: murder, manslaughter, assault, kidnapping/hostage taking, sex offense, robbery, arson, racketeering/extortion, and firearm offenses. Source: United States Sentencing Commission. 2015 Sourcebook of Federal Sentencing Statistics. Table 9: Citizenship of Offenders in Each Primary Offense Category.

After immigration law violations, drug convictions were the next largest category of federal offenses of which non-citizens were sentenced (24%). In contrast, drug offenses accounted for 38% of federal sentences for U.S. citizens.

Undocumented immigrants who receive federal criminal sentences are even more likely to be convicted of an immigration law violation as their most serious offense. Nearly three-quarters (73%) of the 25,670 undocumented immigrants sentenced in federal criminal courts in 2015 were convicted of an immigration offense. In addition, in that year:

• Twenty percent of undocumented immigrants who received federal sentences were convicted of drug offenses (5,218 sentences). As noted above, drug offenses accounted for 38% of federal sentences for U.S. citizens.
• Six undocumented immigrants received federal sentences for murder and manslaughter. This comprised .02% of federal sentences for this group (in contrast to .3% for U.S. citizens). Seen another way, undocumented individuals accounted for 4% of the 143 federal sentences for these offenses. U.S. citizens, in contrast, received 88% of these sentences (126 sentences).

U.S. District Judge Dan Polster has reflected on these outcomes based on his first-hand experience serving as a visiting judge in New Mexico. He noted that of the 200 undocumented immigrants he sentenced, none were convicted of murder, rape, or terrorism. He added: “These are just people who want to be with their family or support their family.”

Conclusion

Before and after his election, Donald Trump has raised concerns about increasing crime and immigration in the United States. Indeed, he has signed an executive order and made regular statements alleging that curbs to unauthorized immigration and dismantling sanctuary cities would reduce U.S. crime rates. The evidence presented here concludes otherwise.

A century of research has shown immigrants do not threaten public safety and, in fact, are less likely to commit crime than native-born citizens. False statements about immigrant criminality contribute to unfounded public fears that threaten the safety of immigrants and U.S. citizens. Improving public safety is a complicated question that cannot be addressed by scapegoating foreign-born residents but rather by investing in effective community-based solutions that address the true causes of crime.

The full report with citations can be found here.