President Donald Trump has been stoking fears about immigrants in the days leading up to the midterm elections. He’s tweeted anti-immigrant ads and threatened to revoke birthright citizenship, something lawmakers on both sides of the aisle have said would be unconstitutional, as he campaigns to drive up Republican turnout.

In a Thursday speech, Trump, a vocal critic of illegal immigration long before he reached the White House, claimed it costs the U.S. billions of dollars each year.

“Illegal immigration hurts Americans workers, burdens American taxpayers and undermines public safety, and places enormous strains on local schools, hospitals and communities in general, taking precious resources away from the poorest Americans who need them most,” Trump said.

Immigration has an overall positive impact on the long-run economic growth in the U.S.

While Trump’s rhetoric has lately focused on unauthorized immigrants, his policies have targeted legal immigration as well. Under his administration, refugee admissions in 2017 dropped to their lowest since at least 2002. Trump signed an executive order tightening restrictions on HB1 visas for skilled immigrants. He has pushed for a merit-based immigration system, and his administration has proposed cutting public benefits to legal immigrants.

Trump’s characterization of immigrants, as people who drain public resources, however, is not backed by the data. Unauthorized immigrants aren’t usually eligible for federal benefits, for instance, and multiple studies have found that immigrants help the economy grow.

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Here are some of the most widespread myths about how immigrants affect the U.S. economy, and the research that refutes them.

Myth #1: Immigrants take more from the U.S. government than they contribute

Fact: Immigrants contribute more in tax revenue than they take in government benefits

A 2017 report from the National Academies of Sciences, Engineering, and Medicine found immigration “has an overall positive impact on the long-run economic growth in the U.S.”

How that breaks down is important.

First-generation immigrants cost the government more than native-born Americans, according to the report — about $1,600 per person annually. But second generation immigrants are “among the strongest fiscal and economic contributors in the U.S.,” the report found. They contribute about $1,700 per person per year. All other native-born Americans, including third generation immigrants, contribute $1,300 per year on average.

It is difficult to determine the exact cost or contribution of unauthorized immigrants because they are harder to survey, but the study suggests they likely have a more positive effect than their legal counterparts because they are, on average, younger and do not qualify for public benefits.

It’s also important to note that less-educated immigrants tend to work more than people with the same level of education born in the U.S. About half of all U.S.-born Americans with no high school diploma work, compared to about 70 percent of immigrants with the same education level, Giovanni Peri, an economics professor at the University of California, Davis, said in a recent interview with PBS NewsHour.

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In general, more people working means more taxes — and that’s true overall with undocumented immigrants as well. Undocumented immigrants pay an estimated $11.6 billion a year in taxes, according to the Institute on Taxation & Economic Policy.

Undocumented immigrants pay an estimated $11.6 billion a year in taxes.

Immigrants are also less likely to take public benefits than the native-born population for two reasons.

First, to receive most public benefits under the social safety net, immigrants must be lawful permanent residents for at least five years.

There are approximately 9 million immigrants that fit that definition in the U.S. Of those, many would not qualify for welfare or other programs because their incomes are too high.

“While it is really important to ensure that immigrants and their children have access to the safety net, there are already a lot of eligibility barriers in place,” said Hamutal Bernstein, a senior research associate at the Urban Institute.