Migration studies have developed rapidly as a research field over the past decades. This article provides an empirical analysis not only on the development in volume and the internationalization of the field, but also on the development in terms of topical focus within migration studies over the past three decades. To capture volume, internationalisation, and topic focus, our analysis involves a computer-based topic modelling of the landscape of migration studies. Rather than a linear growth path towards an increasingly diversified and fragmented field, as suggested in the literature, this reveals a more complex path of coming of age of migration studies. Although there seems to be even an accelerated growth for migration studies in terms of volume, its internationalisation proceeds only slowly. Furthermore, our analysis shows that rather than a growth of diversification of topics within migration topic, we see a shift between various topics within the field. Finally, our study shows that there is no consistent trend to more fragmentation in the field; in contrast, it reveals a recent recovery of connectedness between the topics in the field, suggesting an institutionalisation or even theoretical and conceptual coming of age of migration studies.

It is clear that the field of migration studies has grown significantly over the past decades. What is less known is how this growth has taken place. This article combines bibliometric metadata with expert interviews to analyse the institutionalisation of the field in terms of self-referentiality, internationalisation, and epistemic communities. Self-referentiality in migration studies has gradually increased as the field has grown, until recently. The field has internationalised in terms of international co-authorships but has done so unevenly. Finally, we find that epistemic communities in migration studies, based largely on disciplines, increasingly refer to one another and are increasingly interdisciplinary.

This paper provides an empirical classification of migration-related diversities in 166 European cities. The local turn in migration studies has shown that migration-related diversity may take varied forms in different cities. Our understanding of how and why cities differ is lagging behind the wealth of existing conceptualisations. This is partly because most studies look only at one kind of city, in particular, superdiverse global cities. This paper takes a systematic inductive approach to map the diversity of migration-related diversities in urban setting and understand the reasons behind such variations. Applying quantitative classification methods to European cities in France, Germany, the Netherlands and Italy, we search for a new meaningful classification of the urban diversity configurations based on measures of volume, variety and spread of migration-related diversity. Five empirical clusters of cities of migration are found: superdiverse cities, migrant minority cities, new diversity cities, low-migration cities and non-diverse cities. Subsequently, we develop a better qualitative understanding of these clusters by examining typical cities, their economic positioning, migration history, their policy and political structures, as well as their social and geographical position. A thorough classification, we argue, is necessary to have a more differentiated view of the existing urban diversities and go beyond one-size-fits-all solutions for urban governance of migration-related diversity.

Cities are often the main hubs or portals for migration. They are the places where people leave from, and where they first arrive at, after their migration journey, either to settle or to move on. They are also the places where diversities and mobilities become the most manifest. Built into the cross-roads of ancient trade routes, cities have been the centres for encounters between many cultures since ancient times. In the past, cities attracted internal migrants from rural areas, while nowadays, many cities have been shaped by a long history of international migration. For instance, the development of cities such as New York or London cannot be understood without taking into account their long migration histories. Indeed, in developing countries like Russia, China, South Africa, and Nigeria, urbanisation is still ongoing; both internal rural-urban or periphery-centre migrants, together with international migrants, are attracted to capital city urban centres, and this magnetism in turn shapes diversity landscapes.

Migration studies has contributed significantly to our understanding of mobilities and migration-related diversities. It has developed a distinct body of knowledge on why people migrate, how migration takes place, and what the consequences are of migration in a broad sense, both for migrants themselves and for societies involved in migration. As a broadly-based research field, migration studies has evolved at the crossroads of a variety of disciplines. This includes disciplines such as sociology, political science, anthropology, geography, law and economics, but increasingly it expands to a broader pool of disciplines also including health studies, development studies, governance studies and many more, building on insights from these disciplines.