Forced migration is the coerced movement of a person or persons away from their home or home region. Migrating in the same country means the person is an Internally Displaced Person (or IDP). It often connotes violent coercion, and is used interchangeably with the terms "displacement" or forced displacement. According to Alden Speare, "In the strictest sense migration can be considered to be involuntary only when a person is physically transported from a country and has no opportunity to escape from those transporting him." Movement under threat, even the immediate threat to life, contains a voluntary element, as long as there is an option to escape to another part of the country, go into hiding or to remain and hope to avoid persecution." However this thought has been questioned, especially by Marxians, who argue that in most cases migrants have little or no choice. A specific form of forced migration is population transfer, which is a coherent policy to move unwanted persons, perhaps as an attempt at "ethnic cleansing". Someone who has experienced forced migration is a "forced migrant" or "displaced person". Less formally, such a person may be referred to as a refugee, although that term has a specific narrower legal definition.
The International Organization for Migration defines forced migration as any person who migrates to "escape persecution, conflict, repression, natural and human-made disasters, ecological degradation, or other situations that endanger their lives, freedom or livelihood.”
Forced migration has accompanied persecution, as well as war, throughout human history but has only become a topic of serious study and discussion relatively recently. This increased attention is the result of greater ease of travel, allowing displaced persons to flee to nations far removed from their homes, the creation of an international legal structure of human rights, and the realizations that the destabilizing effects of forced migration, especially in parts of Africa, the Middle East, south and central Asia, ripple out well beyond the immediate region.