Illegal Aliens and Crime Incidence (2007)
March 2007 | Read the Full Report (PDF)
Most Americans equate illegal aliens with a higher incidence of crime. Some academic researchers have attempted to prove that is a misimpression. But, in fact, data show that the American public understands the facts better than the academics.
Adult illegal aliens represented 3.1 percent of the total adult population of the country in 2003. By comparison, the illegal alien prison population represented a bit more than 4.54 percent of the overall prison population. Therefore, deportable criminal aliens were more than half again as likely to be incarcerated as their share of the population.
Misleading Academic Studies
The misleading data produced by academics and think tank researchers that show a lower incidence of crime by aliens is based upon a comparison of data that include all foreign born residents with data for the native born population. Because these data compare all foreign born residents to the native born population, they are largely irrelevant to describing the illegal alien crime incidence.
A lower incidence of crime should be expected from a foreign born population that is largely legal immigrants and long-term nonimmigrants. This population includes persons who are screened for any previous criminal activities before they can get a green card, persons who are again screened for criminal activity before they can become U.S. citizens, and persons such as foreign students and professional workers who are at the least required to state under oath whether they have any criminal history before they can get a visa. In other words, this is a population carefully screened to assure that they are unlikely to engage in criminal activity. Something would be very wrong with our visa screening process if research did not reveal that the foreign-born were less likely to have committed crimes in the United States than the native-born population.
The same cannot, of course, be said for the illegal alien population. Their presence in the United States is based on their either illegally entering the country or entering under false pretenses. Those who sneak into the country undergo no form of screening for criminality or any other grounds for exclusion. Many in the illegal alien population end up incarcerated as a result of criminal activity at the time of their illegal entry, e.g., drug smuggling or alien smuggling. Other illegal aliens owe alien smugglers for assisting their illegal entry and end up being co-opted into criminal activity, such as drug distribution or prostitution, to pay off the debt.
The apparent linkage between illegal alien status and a higher incidence of crime was suggested in the data presented in a recent study of the costs of illegal immigration in Arizona. That study noted that Arizona in 2000 had the highest per capita rate of illegal aliens in the country and also ranked at the top of a number of crime indexes. It had the nation’s highest per capita rate of property crimes, the highest rate of vehicle theft, and the 2nd highest rate in the country of larceny theft. For burglaries, it ranked 5th, for murders 9th, and for robberies and aggravated assaults it ranked 15th in the country.
There is nothing about the population in Arizona that would appear to explain this pattern of crime incidence other than the illegal alien population and the proximity to the border with Mexico.
Findings Using SCAAP Data
To obtain a valid view of the incidence of criminal activity by illegal aliens in comparison to the general population, it is necessary to focus just on that segment of the population. The only data that directly identify criminal illegal aliens depend on resources of the federal government. The federal State Criminal Alien Assistance Program (SCAAP) is administered by the federal government to reimburse states and local jurisdictions for costs incurred for the incarceration of criminal aliens. It offers the only reliable data for a valid assessment of the share of prisoners who are deportable aliens.
In that program, states and local jurisdictions may submit names and records of persons known or believed to be illegal aliens to the Department of Justice. Those records are vetted to eliminate persons who are U.S. citizens and any aliens whose incarceration does not make them deportable. Data reported in the SCAAP reimbursements were used in this study to determine the correlation between the size of the criminal alien population and the non-criminal alien population.
Methodology and Findings
Data collected in the SCAAP reporting system were stated in terms of incarceration days. This eliminates any distortion based on length of sentence. Nationwide there were nearly 600 million incarceration days reported, and the number of those days attributable to identified and suspected illegal aliens were about 24.5 million incarceration days. That suggests that one of every 22 prisoners is a deportable alien (4.54%).
The comparison of this prisoner population with the population at large requires identifying a comparable population. Clearly only adults or near adults are likely to be in this population. To obtain an estimate of adult illegal aliens the INS estimates can be used, even though they probably understate the size of that population. To adjust those estimates to a population comparable to an adult population the only available resource is to reduce the INS estimate by an estimate of illegal alien school-age population. The estimate of illegal alien school-age children, done in an earlier study, provides a rough estimate of the K-12 population by state. Because of the age profile of this group, there will be some pre-K illegal aliens and post-grade 12 illegal alien teenagers included in the resulting estimate of a bit more than 7 million illegal aliens in 2000. The comparable adult national population in 2000 is about 228 million persons, and the comparison of these two data sets yields a 3.1 percent share of the adult national population that is comprised of illegal aliens, i.e., one in every 36 adult residents in the country.
Thus the likelihood that an illegal alien will be among those incarcerated (1 in 22) is significantly greater than the share of adult illegal aliens in the country (1 in 36). It is this greater likelihood of being incarcerated that clearly demonstrates that illegal aliens are disproportionately involved in criminal activity.
The data show a clear pattern both nationwide and in the states with the largest estimated illegal alien populations of a higher rate of incarceration of aliens than for the non-alien population. However, the pattern is not uniform. In five of the 13 states with estimated illegal alien populations of over 100,000 in 2000, the reverse was true. Those states were Georgia, Illinois, and North Carolina, Texas and Virginia.
Looking at those 13 states as a whole, in 2000 they had about 54 percent of the country’s adult population and more than 85 percent of the estimated adult illegal alien population. They also had about 61 percent of the total amount of total criminal incarceration reported in SCAAP and more than 85 percent of the deportable alien incarceration reported in that program.
These calculations demonstrate that the rate of incarceration overall was both higher in these 13 states than in the country as a whole and much higher than in the remaining states and the District of Columbia taken together. Nevertheless, in the rest of the country, the average estimated adult illegal alien share was one percent and the related share of the incarcerated illegal alien share was nearly twice as large (1.7%).
The states that had the highest rates of incarcerated aliens when compared to the share of the estimated illegal alien adult population were, in order, New York, Washington, Florida, Arizona, and California. In each of these states the alien prisoner population represented more than five percent of the total prisoner population, and in California, the share was higher than one in every nine prisoners.
- This calculation is based on the estimate of the Immigration and Naturalization Service released after studying the results of the 2000 Census that there were about 7 million illegal aliens in the country. This was about 2.5 percent of the total population found in the Census. The percentage of illegal aliens in the adult population is a bit higher because the share of illegal alien children is smaller than children in the population at large. For comparability with the 2003 SCAAP survey data, Census Bureau 2003 population estimates were used, and the illegal alien population estimate was increased by 1.5 million persons — yielding an increased share of 2.9 percent of the total population.
- See for example: Rumbaut, Ruben G. and Walter A. Ewing, “The Myth of Immigrant Criminality and the Paradox of Assimilation: Incarceration Rates Among Native and Foreign-Born Men,” Immigration Policy Center, Spring 2007.
- Martin, Jack and Ira Mehlman, The Costs of Illegal Immigration to Arizonans, FAIR, May 2004.
- Data and rankings were taken from FBI, Uniform Crime Reports (http://www.fbi.gov/ucr/ucr.htm).
- SCAAP program data for FY 2003 were used because they identified the total days of prisoner detention, those of suspected deportable aliens, the disallowances by the federal government, and the allocation of the incarceration data by state.
- Martin, Jack, Breaking the Piggy Bank: How Illegal Immigration Is Sending Schools into the Red, FAIR, June 2005.