Some research suggests that immigration can offset some of the adverse effects of automation on native labor outcomes. By increasing overall demand, immigrants could push natives out of low-skilled manual labor into better paying occupations. A 2018 study in the "American Economic Review" found that the Bracero program (which allowed almost half a million Mexican workers to do seasonal farm labor in the United States) did not have any adverse impact on the labor market outcomes of American-born farm workers. A 2019 study by economic historians found that immigration restrictions implemented in the 1920s had an adverse impact on US-born workers' earnings.