Whereas the impact on the average native tends to be small and positive, studies show more mixed results for low-skilled natives, but whether the effects are positive or negative, they tend to be small either way. Research indicates that immigrants are more likely to work in risky jobs than U.S.-born workers, partly due to differences in average characteristics, such as immigrants' lower English language ability and educational attainment. According to a 2017 survey of the existing economic literature, studies on high-skilled migrants "rarely find adverse wage and employment consequences, and longer time horizons tend to show greater gains".