 A literature review of the economic impacts of immigration finds that the net fiscal impact of migrants varies across studies but that the most credible analyses typically find small and positive fiscal effects on average.According to the authors, "the net social impact of an immigrant over his or her lifetime depends substantially and in predictable ways on the immigrant's age at arrival, education, reason for migration, and similar".Studies of refugees' impact on native welfare are scant but the existing literature shows mixed results (negative, positive and no significant effects on native welfare).