Ofta hävdas att temporära uppehållstillstånd försvårar integrationen pga den osäkerhet de skapar. Men teoretiskt kan man tänka sig motverkande effekter av att det blir svårare att få stanna så länge det finns åtminstone någon chans att få permanent uppehållstillstånd. Här är en studie av Matilda Kilström, Birthe Larsen och Elisabet Olmesom som hittar vissa sådana effekter i Danmark:
We study a Danish reform in 2002 that lowered the ex ante probability of refugees receiving permanent residency by prolonging the time period before they were eligible to apply for permanent residency
Resultaten ter sig tämligen intuitiva:
the reform significantly increased enrollment in formal education, especially for females and low skilled individuals. In terms of employment and earnings, coefficients are in general negative but non-significant. ... The reform had a negative impact on criminal activity driven by a reduction among males. There are no effects on health outcomes and significant but relatively small negative effects on childbearing for females. The results do not seem to be driven by selection, since the reform had no significant effect on the share that stayed in Denmark in the long run.