In the context of guest workers, can we be confident the person will leave the country after their visa expires? Do we know that a refugee is not secretly harboring terrorist sympathies? The officers doing the screening of potential entrants are unlikely to be able to elicit such information from interviews. Furthermore, home state governments may not have reliable information themselves. Indeed, there may be an inverse relationship between the quality of record-keeping in a nation and the likelihood that it is a source of refugees. Ultimately it is only the immigrants themselves who have full information about their trustworthiness.

There’s another complication. Even if screening were 100 percent effective, people’s intentions and positions can change. A guest worker who originally planned to return to her home country may face altered personal circumstances and seek to stay. More grimly, a member of an immigrant community might become alienated once in the United States, become associated with similarly disgruntled people and begin to engage in hostile activity. We hasten to add that statistical evidence shows that this is extraordinarily rare. Still, alienated immigrants, however few in number, make up a larger proportion of bad actors than so-called Trojan Horse immigrants and refugees.

When you reframe vetting as an informational challenge, it opens the door to novel solutions. Our proposal is something we call a “trust circle” — a concept that borrows from cutting-edge ideas that some lenders in the developing world are already using to judge the reliability of people lacking credit records. The key idea is to make use of information from those who can best assess the likely behavior of entrants: members of immigrant communities themselves.

Read more at Vox