That test is known as the "public charge" law, which allows federal immigration authorities to deport immigrants who become dependent on social programs; they also can prevent legal immigrants applying for green cards from obtaining them for the same reasons. Individuals living in the United States whose relationships with family members make it possible for their relatives to apply for entry into the United States are required to sign an affidavit attesting to the fact that they earn a sufficient income to support themselves and any family members hoping to immigrate. Anyone signing such an affidavit also agrees to pay back certain public assistance should their relatives who hope to immigrate ever receive it.