Quick Answer: Immigration is the international movement of people to a destination country of which they are not usual residents or where they do not possess nationality in order to settle as permanent residents. Commuters, tourists, and other short-term stays in a destination country do not fall under the definition of immigration or migration; seasonal labour immigration is sometimes included, however. Economically, research suggests that migration can be beneficial both to the receiving and sending countries. The academic literature provides mixed findings for the relationship between immigration and crime worldwide. Research shows that country of origin matters for speed and depth of immigrant assimilation, but that there is considerable assimilation overall for both first- and second-generation immigrants. Discrimination based on nationality is legal in most countries.