For the last two years, the Trump Administration has continually cited the burden that undocumented immigrants place on the US economy as justification for its “zero tolerance” border policy. Trump has personally referred to Latin American immigrants as “animals” that want to “infest” the United States. He has repeatedly, and falsely, referred to the influx of refugees fleeing violence in the Middle East as a major problem for Europe as justification for his administration’s hard line stance on immigration in the US.

As recently as Monday, Trump tweeted about a “big mistake made all over Europe in allowing millions of people in who have so strongly and violently changed their culture!” Yet according to new research published today in Science Advances, asylum seekers in Europe have actually positively benefited the economies of their host countries.

The research was jointly conducted by the French National Center for Scientific Research, Clermont-Auvergne University and Paris-Nanterre University, and uses economic data from 15 different Western European countries with the highest asylum application rates between 1985 and 2015.

Throughout the 90s, Western Europe saw a large increase in asylum seekers following the wars in the Balkans. In the last seven years there has been another increase in asylum seekers in Europe as people flee the instability of countries affected by the Arab Spring or the Syrian civil war. At the same time, the researchers note, the flows of migrants have increased as the European Union expanded eastward in 2004.

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To see the impact of asylum seekers and migrants on economic indicators such as Gross Domestic Product per capita, unemployment, and public finances, the researchers used a statistical model developed by the Nobel Prize-winning economist Christopher Sims. This model gave the researchers a better picture of how asylum seekers affect national economies compared to other models, which consider the economic impact of migrants as an input-output equation (i.e., how much is paid to them by the government versus how much they pay in taxes), but don’t take into account other economic interactions captured by Sims’ model.

The researchers found that permanent migrants actually had a net positive impact on the economy of their host country. GDP per capita “significantly” increased and unemployment rates fell. Moreover, the researchers found that “the additional public expenditures, which is usually referred to as the ‘refugee burden,’ is more than outweighed by the increase in tax revenues.”

Asylum seekers also had net positive effects on the economies of their host country, but it takes a little longer to appear. According to the research, positive economic effects from asylum seekers similar to those of other migrants are seen three to seven years after seeking asylum in the country, the point at which some of them become permanent residents of their host country.