David J. Bier
David J. Bier

Just before the election, the Manhattan Institute (MI) released a report titled “Lifetime Fiscal Impact of Immigrants.” MI claims that the recent surge in immigration under President Biden will cost the federal government $1.15 trillion over the lifetimes of these new immigrants and that “mass deportations would significantly reduce the national debt.” Expect this analysis to be cited by the incoming Trump administration.
Today, the Cato Institute has published my response as a working paper, detailing serious errors that, when corrected, reverse MI’s central conclusion. In fact, after corrections, MI’s model predicts enormous fiscal benefits from the recent influx of illegal immigrants: a deficit reduction of $4.9 trillion over the immigrants’ lives. This is consistent with the recent findings of the Congressional Budget Office (CBO). 
Here are the nine major issues my paper identifies:

MI assumes that immigrants cause large, immediate increases in military spending;
It excludes significant tax revenues from corporations employing the immigrants;
It inaccurately attributes the costs of the child tax credit solely to parents;
It assumes that low-skilled immigrants are just as unlikely to leave the US before retirement as high-skilled immigrants;
It doesn’t account for how immigrants reduce interest payments on the debt;
It assumes new illegal immigrants are as uneducated as those from a decade ago;
It assumes recent illegal immigrants are as old as other immigrants;
It assumes illegal immigrants are just as likely to use entitlements as other groups; and
It fails to account for interest costs on deportation spending.

Even if you correct only the last item on this list, MI’s estimated deportation costs jump to $1.6 trillion, which exceeds the supposed benefits of mass deportation. The report’s author helpfully shared the model so I could reevaluate its results precisely. 
#1 Military spending: MI states that military spending will increase because more people will mean more military personnel,  » Read More
https://www.cato.org/blog/errors-mar-report-claiming-mass-deportation-cuts-debt