Migration deterrence has become a prominent plank of aid policy, with the EU pledging €3bn to tackle the “root causes” of migration from Africa, while the US has made migration deterrence part of its development assistance to Central America.

Such aid programmes are often focused on supporting long-run economic growth, more jobs for young people, conflict reduction and improved human rights in the hope that people will stay at home rather than seeking opportunities elsewhere.

However, a CGD briefing, Can Development Assistance Deter Emigration?, noted there was little evidence that aid can achieve these outcomes.

“This is not to say that aid cannot affect conditions in major migrant-origin countries in the future,” the report said.

“But aid would need to act in unprecedented ways, at much higher levels of funding and over generations, to sufficiently affect drivers of migration.”

The authors, Michael Clemens and Hannah Postel, suggested the relationship between migration and economic development was complex.

“Greater economic opportunity at home may decrease the incentive to invest in working abroad, but may also make such an investment more feasible,” they said.

They noted that emigration from middle-income countries was typically much higher than from poorer countries, suggest that economic development does more to stimulate migration than to stop it.

Clemens and Postel argued that, with large-scale migration set to continue for the foreseeable future, policymakers needed to look beyond deterrence.

“Aid agencies should…focus on co-operation with migrant-origin countries to shape how migration occurs,” they concluded.