The deportation force is being mustered.

President Donald Trump is making good on his campaign promise to round up and deport undocumented immigrants more aggressively than prior presidents. He recently told business leaders at the White House that a “military operation” is underway to roust people who are in the country illegally, and John Kelly, the Director of Homeland Security, recently outlined plans to hire 15,000 new immigration agents to help with the work. That will take time—and require Congressional funding—but the Trump administration already seems to be ramping up enforcement of existing immigration laws.

Trump has blamed undocumented immigrants for taking American jobs, committing violent crimes and milking US taxpayers. There are certainly anecdotal examples of each, but Trump also applies his usual hyperbole to the issue, while overlooking the important role undocumented workers play in the US economy. They account for about 4.5% of the American workforce and are crucial workers in industries such as agriculture, construction and hospitality. If Trump intends to kick an estimated 11 million undocumented people out of the country, it could upend many businesses and harm the economy more than it helps.

[Related: Trump wants to block immigrant workers companies need.]

“Will US workers come in and ask for those jobs? I’m guessing not without a big pay raise,” says Jennifer Van Hook, a demographer at Penn State University who has studied illegal immigration in depth. “There’s going to be a labor shortage in certain industries, especially if these people really do leave.”

Many people conflate legal and illegal immigration, which are actually quite different. The majority of people in the country illegally arrived with legal visas, and simply stayed once the visa expired. A smaller portion snuck in without any paperwork at all. Some of those are the “really bad dudes” Trump rails against, but most aren’t. Here are 5 myths about illegal immigration that are obscuring the economic importance of such people:

Illegal immigration is getting worse. Trump has talked about America’s “open borders” as if foreigners are suddenly flooding into America. That’s not what is happening. Illegal immigration peaked in 2007, and has since drifted down, according to the Pew Research Center. Fewer people have been coming from Mexico, while more have been coming from Central America. Here’s the overall trend:

Undocumented immigrants don’t have jobs. Trump frequently cites a controversial study saying 62% of the unauthorized population collects some kind of welfare, as if people sneak into the United States just for taxpayer-funded benefits. (More on that dubious claim below.) In reality, about 60% of undocumented immigrants—roughly 6.4 million of the 11 million—have jobs. The portion of undocumented, working-age men with a job is 87%, according to research by Harvard University economist George Borjas. The employment rate for American men is much lower—74%. “A frequent conjecture is made about undocumented immigration—that ‘undocumented immigrant men come to the United States to work,’” Borjas wrote in a 2016 study. “The data strongly support this conjecture.” Undocumented women are less likely than American women to work, probably because they are more likely to have children.

[Related: Trump now owns Obamacare.]

Those who do work take American jobs. Trump rightly asserts that most undocumented workers are lower-skilled, undereducated people. But it’s unlikely they take many jobs Americans would otherwise have. Borjas’s research, for instance, found that undocumented immigrants are “far less responsive to wage changes than the labor supply of natives.” That means they’ll work even if pay drops or low-paying jobs are replaced by even lower-paying ones – probably because they have no other choice. Americans, by contrast, have resources such as unemployment insurance and other types of programs to palliate the sting of economic hardship. The data suggests American workers simply don’t want or need the low-paying jobs often done by foreigners. Plus, of the 10 states with the highest percentage of undocumented immigrants—Nevada, Texas, California, New Jersey, Arizona, Florida, Maryland, New Mexico, New York and Colorado—7 have an unemployment rate equal to or lower than the national average of 4.9%. If undocumented immigrants were putting Americans out of work, unemployment ought to be higher than average in those states, not lower.

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