One of the top researchers on the effects of immigration on native workers’ wages has produced a new study that finds that an increase in low-skilled immigration pushes native workers into more complex jobs, raising their wages.

The question of how low-wage native workers are affected by immigration is hotly contested among academics. Giovanni Peri, an economist at the University of California, Davis, known for immigration research, examined the effects of a mass migration of Bosnian, Somalian, and Iraqi refugees to Denmark over 1991-2008. Along with the Danish researcher Mette Foged, Peri discovered that the result of the influx of low-skilled migrants was that Danish workers, over time, were pushed into new, more complex jobs, an effected more pronounced in cities with higher levels of immigrants. For both high-skilled and low-skilled Danes, that process resulted over time in higher wages.