This document provides an overview of key concepts relating to population migration, including:
1) Definitions of migration terms like migration, circulation, push and pull factors. Migration is defined as movement between administrative regions while circulation covers shorter trips.
2) Causes of migration like economic, social, political factors that can push people to leave a place or pull them to a new one.
3) Types of migration by timescale (daily to permanent) and space (local to international).
4) Examples are given of migration rates and top sources and destinations of international migrants worldwide.