International migration is frequently discussed in association with development. There are some 232 million international migrants in the world (UN DESA, 2013), and when internal mobility is included this number jumps to one in seven people on the planet. These numbers emphasize the increasing significance of migration. Yet the topic remains a complex phenomenon. Great variations in the conditions faced by migrants are mirrored in its developmental impacts. Furthermore, migration can also be seen as a product of development. From the early movements of huntergatherers, to urbanization processes triggered by the industrial revolution, to the movement of health workers triggered by ageing populations, mobility is a core part of the human experience.

When we talk about migration and development in policy circles we tend to focus on how we can enhance the positives and mitigate the negatives. In doing so, there is often more of a focus on the more tangible channels through which migration can impact development: remittances, diaspora engagement and the highly skilled, and less so on other less tangible areas such as social remittances, and the reverse relationship between migration and development, where development impacts migration.

However, these areas merit further investigation, because they lead us to consider what the evidence tells us about how migration, like technology or international trade, transforms realities. Additionally, internal migration has not been given the recognition it deserves within international frameworks, particularly given that urbanization processes are inherently linked to both migration and development.

It is clear that migration should be part of the discussions for the post-2015 development agenda. However we should tread with caution. Migration is also a topic that questions national sovereignty and, as such, an emotive and controversial topic in parliaments across the world.