Immigrants’ Deportations, Local Crime, and Police Effectiveness

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Despite popular belief, academic studies find little correlation between immigration and crime rates in the United States. Most find that immigrants are less likely to commit crimes and less likely to be incarcerated than similar native‐​born Americans, and even undocumented immigrants have lower conviction and arrest rates. There is evidence that immigration decreases local crime rates but no evidence that the presence of undocumented immigrants is associated with more crime. More recent research examines the impact of increased enforcement on local crime. For example, studies find that the E‑Verify program, which allows employers to check the work‐​eligibility status of their employees, reduced the population of young males in Arizona and thus reduced the occurrence of property crime by changing Arizona’s demographic composition. Overall, the literature finds a negative or null association between immigrants and crime.

Immigrant deportations that explicitly prioritize removing people convicted of a crime, some advocates claim, are a more direct enforcement policy to meet the goal of reducing crime. The Trump administration has claimed that undocumented immigrants pose a security risk to justify increased deportations. This recent surge in deportations under President Trump is not the first time the U.S. federal government has taken a harder line on immigration enforcement. As early as 1929 – 1934, the United States carried out a forced repatriation of about 500,000 Mexicans and Mexican Americans, claiming this would improve work opportunities for native‐​born Americans. More recently, in the period 2008 – 2012, the United States deported substantially more undocumented immigrants than it had in past decades. The stated intent was to remove serious criminals and reduce local crime. However, few studies have attempted to test these claims. Were enforcement policies effective at reducing crime rates or increasing police effectiveness? Our work seeks to answer this question empirically by identifying the impact of deportations on local crime rates and on police effectiveness in solving crime by arresting perpetrators.

Deportations should reduce crime if the deported people are serious criminals or more likely to commit crimes in the future. If people who commit immigration violations are also more likely to commit other offenses, as some politicians claim, enforcement programs that provide immigration information to the police and trigger the involvement of federal agents who can detain and deport undocumented immigrants may help local law enforcement prevent crimes. In 2008, the Department of Homeland Security launched Secure Communities (SC) as a tool to engage the resources of local police in federal immigration enforcement efforts by screening anyone booked into jail, no matter the reason, for immigration violations. Immigration and Customs Enforcement, the federal immigration enforcement agency, could then take custody of any person found to have violated immigration law. Between its introduction in 2008 and temporary suspension in 2014, SC led to more than 450,000 deportations.

Our analysis considers whether more intense immigration enforcement, as measured by deportations per population, decreased crime rates for violent offenses or property offenses. First, we document that the staggered introduction of SC significantly increased the risk of deportation for undocumented immigrants once introduced. Then we estimate the effect the deportation rate, measured as the number of deportations divided by the adult population, had on changes in crime rates. Deportations may be endogenous: unobserved factors, such as local attitudes toward undocumented immigrants or changes in police behavior, may impact both the local intensity of immigration enforcement and crime rates. Therefore, to identify a causal effect of deportations on crime, we focus on deportations driven by the start of the SC program, rolled out in a quasi‐​random way, and that interacted with the local presence of likely undocumented immigrants in 2005. To capture potential local economic effects of the Great Recession, we control for industry‐​specific employment shares in construction and manufacturing. In addition, we check that the timing of the rollout of SC was not correlated with pre‐​2008 trends in crime, economic characteristics, and demographics.

Our main findings show that increased deportations did not reduce local crime rates. The estimated effect on violent crime is small and not statistically significant. The effect on property crime is also small. In most cases, the number of people removed by deportation did not have a large impact on the undocumented population at the local level. On average, 1 percent of the likely undocumented population was deported, although the share was as high as 10 percent in some counties. This is likely too small a share to see a significant effect on crime from compositional changes. Deportations may also affect the undocumented population if immigrants move in response to more intense enforcement in an area. However, we do not find a significant correlation between deportation rates and changes in the likely undocumented population, suggesting that SC did not reduce the net undocumented population. Of course, heightened enforcement may have still deterred crime if it had reduced the propensity of the targeted population to commit crimes, but this seems unlikely considering we do not find an impact on crime rates or demographic composition.

Beyond removing criminals, SC may have indirectly impacted police efficiency and resources by altering how local law enforcement allocated limited resources and by changing the demands on those resources. To measure changes in police efficiency, we examine the local clearance rate (or the number of crimes cleared by arrest) relative to all crimes reported in a year. To check whether SC impacted police resources, as SC put higher demands on the local law enforcement by requiring jails to detain potential violators of immigration law, we examine the number of law enforcement personnel per capita. We do not find any evidence that increases in the deportation rate affected police efficiency or altered the level of police resources. Finally, SC could have affected crime indirectly by changing local employment opportunities or firm creation. However, we do not find evidence of unintended economic consequences through firm creation or the employment of less‐​educated workers.

This research brief is based on Annie Laurie Hines and Giovanni Peri, “Immigrants’ Deportations, Local Crime and Police Effectiveness,” June 2019, http://​ftp​.iza​.org/​d​p​1​2​4​1​3.pdf.

Annie Laurie Hines and Giovanni Peri

Annie Laurie Hines, University of California, Davis; and Giovanni Peri, University of California, Davis, and IZA.