Illegal Immigrants Cause 6% of Crime , which Costs$24 Billion

David Wilson pointed out flaws in my earlier post on crime and illegal immigrants. My numbers were way off, but even when cut they support my ultimate conclusion: the cost of crime by illegal aliens wipes out the economic gains from them. And this is true even if it were to be the case, as Mr. Wilson suggests, illegal aliens have a lower propensity to commit crime---adjusting for age, sex, ethnicity, etc. --- than citizens do. (That's because for the question of how much they harm the U.S. , one shouldn't adjust: what matters is how much crime they commit in total, not how much crime they would commit if they were old and female.)

Note that even corrected, my estimates are still just a weblog estimate, not up to the standards for first draft for an academic working paper, though that doesn't mean they aren't the best available (somebody *should* do a serious study of this). What would be really useful would be a survey of a random sample of those imprisoned in state and federal prisons and jails.

My numbers were indeed way off. The big problem was my use of the SCAAP numbers for the number of illegal aliens in jail during the year. I compared that to the number of people in jail measured on one particular day. Since jails are for terms of less than one year, there will be a lot more people in and out during the year than are in jail during any one day.

My latest estimate is that 6.1% of crime is by illegal aliens, and it imposes a cost of 24 billion dollars per year. The reasoning is below. (The percentage is exactly the same as David Wilson's but that is an odd coincidence; he includes jails and gets 6.1% as 131,000/ 2,135,335).

Here are some numbers on inmates of "prisons" (a term of art which means state and federal prisons, places where criminals serve sentences of one year or more, as opposed to jails, which are run by cities and counties for lesser offenders). K means "thousand".

From the Justice Dept. source on prison data: Prison and Jail Inmates at Midyear 2006, http://www.ojp.usdoj.gov/bjs/abstract/p06.htm, or http://www.ojp.usdoj.gov/bjs/pub/pdf/pjim06.pdf Appendix Table 6: In prisons: 33K federal, 57K state noncitizens on June 30, 2006. Total: 90K. Table 12: Prisoners in custody: 181K federal, 1290K state. Total: 1471K. Fraction noncitizen: 90/1471= 6.1%.

If there are 10.5 million illegal aliens, then their imprisonment rate is 90/10500 = 0.85%. There are 308 thousand Hispanics in prison p06t07.csv out of a population of 44.3 million (Stat Abs. Table 6), about 0.69%. Thus, illegal aliens aren't much different from hispanics in percentage imprisoned. That is surprising, since I would think the illegals would have fewer women and children to bring down the criminality rate. The overall US imprisonment rate is 1471/297000=.50%. The white (nonblack, nonHispanic) rate is .27% (= (478+49)/198000 ) and the black (nonhispanic) rate is 1.56% (=(534+28)/36000).

The prison data has some problems. It is not just for the 10 million or so illegal aliens, but for all noncitizens, which includes the 12 million or so legal aliens (people with green cards, tourists, etc.) (10.5 million illegal aliens from the Statistical Abstract: http://www.census.gov/compendia/statab/tables/08s0046.pdf The total population was 296,639,000, That's about 3.4% illegals.) (Legal aliens in 2005: 20.7-10.5 million. Table 44 SA http://www.census.gov/compendia/statab/tables/08s0044.pdf) Also, (1) some states don't report, (2) some states report jails as well as prisons, and (3) some states report all foreign-born, not just illegal aliens.

Also, from GAO report number GAO-05-337R, ‘Information on Criminal Aliens Incarcerated in Federal and State Prisons and Local Jails’ which was released on May 9, 2005, criminal aliens incarcerated in federal prisons were 49K at year-end 2004, a lot more than the 33K above; and in fiscal year 2002-SCAAP reimbursed states for 77K criminal aliens. The 77K is compatible with the 57K above, since it's 4 years apart and not just year-end (some people even with sentences of over a year will have left by year-end).

Anyway, if illegal aliens are 6.1% of crime (making the further assumption that the percentage in prisons is equal to the percentage of crime generally,including less serious crime), then if crime costs $400 billion per year, crime by illegal aliens costs 24 billion dollars per year. That is about equal to the June 20, 2007 CEA report Immigration’s Economic Impact, which says immigration has a net benefit of $30 billion per year, which includes both legal and illegal immigrants.

May 3: A survey of illegal immigrants who applied for amnesty around 1989 found that of working-age adults, just 57% were male and 12% worked in agriculture. 37% had 9 or more years of schooling, which is below the American average, but above the Mexican average (p. 884 of Illegal Migration from Mexico to the United States Gordon H. Hanson, Journal of Economic Literature, Page 1. The Journal of Economic Literature Vol. 44, No. 4, December 2006)