Theories of Migration

International migration is such a diverse and complex issue that no single hypothesis has been able to provide a complete explanation. Including a diversity of views and circumstances improves our understanding of the causes of international migration.

The different reasons for the authorization permits granted to third-country migrants in the EU, and, second, that the distinction between forced and voluntary migration has become increasingly blurred. Residence permits and first asylum applications from Sub-Saharan Africa to the EU.

Gravity Model

The Gravity model was created by William J. Reilly in 1931. The model tries to predict the movement of people and goods between two places. It was based on Newton's gravitational law. This model looks at distance and population size to determine the likelihood of migration.

The gravity model of migration is based upon the idea that as the importance of one or both of the locations increases, there will also be an increase in movement between them. The farther apart the two locations are, however, the movement between them will be less. This phenomenon is known as distance decay.

Formula  = Population 1 X population 2

Distance (squared)

The gravity model can be used to estimate:

• Traffic flow
• Migration between two areas
• The number of people likely to use one central place

This model also explains states only distance does not matter, if the place of destination has more opportunities, services, and wealth hence larger, then people migrate more to that place.

• If the city is closer, you will interact with it more.
• if the city is larger, you will interact with it more.

Critique of the gravity model

Opponents of the gravity model explain that it can not be confirmed scientifically, that it's only based on observation. They also state that the gravity model is an unfair method of predicting movement because it’s biased toward historic ties and toward the largest population centers. Thus, it can be used to perpetuate the status quo.

Neoclassical Theories - Macro, Micro, Equilibrium

This theory assumes that labourmarkets and economies move towards equilibrium in the long run through trade and migration. It considers migrants as purely rational actors. Migrants move from societies where labouris abundant and wages are low, to societies where labouris scarce and wages are high. Decisions to migrate are taken at the individual level and consider that higher earnings, in the long run, compensate for the cost and risk of relocating.

Neoclassical Theory: The macro level

This was the earliest theoretical framework developed to explain labour migration. It sees migration as the result of geographical differences between labour supply and labour demand. These differences can exist at the international level or at the internal (or national) level.

International migration is caused by the differences in wage levels between countries and labour markets. If wage differences were eliminated, labour migration would stop according to this theory.

This theory suggests that the bulk of labour migration moves from capital-poor/labour force-rich countries to capital-rich/labour force-poor countries, while by contrast capital moves in the opposite direction, expecting a higher return on investment made in capital-poor countries.

This theory also suggests that high-skilled workers move from capital-rich to capital-poor countries to reap higher returns on their skills.

Labour markets are the main mechanisms that influence international migration. Other markets have little role. Thus, governments can regulate migration through labour market policies (e.g. through wage increases in sending countries).

Neoclassical Theory: The micro level

This variety of neoclassical economics theory refines the arguments at the macro level by suggesting that international labour migration is caused by differences in wage and employment rates and that migrants EXPECT their wages to be higher in the destination country.

This theory argues that potential migrants estimate the costs and benefits of moving to alternative locations. In theory, they migrate where they expect the greatest returns over a specific period of time. The human capital of each migrant may increase her/his probability of employment in the destination country as well as her/his expected earnings and therefore affects the probability of each individual to move.

So, this theory not only includes wage differentials in the analysis but also individual features that determine employment and wages, as well as general social conditions and technologies that lower the cost of migration. All these elements can raise the probability of a person migrating.

Migration is anticipated to continue to occur until expected earnings (wages plus probability of employment) have been equalized internationally.

In short, migration decisions according to this theory are taken by the individual and stem from differences in labour markets. Costs of migration include also social and emotional costs. Governments can influence immigration primarily through policies that affect expected earnings in origin and destination countries.

New economics theory of migration

This theory focuses on the nexus between people at origin and destination. Migratory movements are often connected to prior long-standing links between sending and receiving countries, like commercial or cultural relationships. These give birth to migration systems, i.e. two or more countries exchanging migrants, and migration networks, such as circular and diaspora-based migrations. People move where they can rely on someone they know. The processes are cumulative and do not necessarily tend to an equilibrium: the more the diaspora expands the more it will attract new migrants.

A variation of the Neoclassical, this theory incorporates the societal dimension in the decision to migrate. The migration decision is often taken collectively, especially within households. The migration of selected family members may be used to mitigate risks and diversify income resources for the entire family. If things go well for the ones who migrate, they will provide support for their families in the country of origin, and vice versa.

The new economics of migration theory has a different point of departure compared to neoclassical economics and challenges both the micro and the macro approaches outlined above.

According to this theory, the decision to migrate is not made by isolated individual actors: it is the result of a collective decision to maximize income and employment opportunities and minimize risks.

Developed countries minimize risks through welfare states and insurance systems. So, for example, if a crop fails, there are crop insurance markets. There is also access to futures markets to obtain guaranteed prices for selling agricultural products. If someone is injured or loses their job, there are unemployment benefits. If someone seeks to improve their business, there are credit institutions and capital markets that provide loans.

In developing countries, all these risks have to be faced by the household. Hence, migration is a strategy to diversify risks. The main incentive to migrate is not only to raise income but also to diversify risks. International migration may occur alongside increases in local employment and production. It does not have to stop when wage differentials disappear.

This theory also introduces the notion of relative deprivation: migration can alter income distribution within a community and therefore lead to more people deciding to migrate.

Governments can influence migration not only through labour market policies but also through policies on the other markets identified above (insurance, credit, etc.).

Stark (1984) argues that, as migration is a choice and people's choices are affected by their level of satisfaction or deprivation relative to the community they belong to, migration decisions are motivated by minimization of relative deprivation, not by absolute income maximization.

Moreover, government policies in sending countries that raise the mean income of the population but leave behind the poorer households may increase the probability of migration.

Intervening Opportunities by Stouffer

According to Stouffer, Migration is not related to the distance and population size of the city as the gravity model claimed but it is dependent on the number of opportunities available in that location.

Stouffer's law of intervening opportunities states, "The number of persons going a given distance is directly proportional to the number of opportunities at that distance and inversely proportional to the number of intervening opportunities."

Stouffer theorizes that the amount of migration over a given distance is directly proportional to the number of opportunities at the place of destination and inversely proportional to the number of opportunities between the place of departure and the place of destination. These intervening opportunities may persuade a migrant to settle in a place in the route rather than proceeding to the originally planned destination. Stouffer argued that the volume of migration had less to do with distance and population totals than with the opportunities in each location

Opportunities and intervening opportunities are:

• Economic opportunities such as good job opportunities, proper houses
• Sanitation, health, and education facilities
• Entertainment facilities
• Clean environment
• Political stability, security, and political opportunities
• Cultural and social opportunities.

Dual Labour Market Theory

According to dual labour market theory, migration is caused by pull factors in developed countries and not by push factors in sending countries. It is the economic structure of developed nations that requires a permanent supply of labour.

The need for cheap workers in modern societies is the main factor explaining migration, according to this theory. The demand for labourin developed economies pulls migrants independently from the labouror wage conditions at the origin societies. At the receiving economy, the labourmarket is segmented: the native-born have access to careers, good pays and safe working conditions; migrants are channeled to labor-intensive secondary or tertiary sectors that provide precarious jobs, low pays, and hazardous working conditions.

Advanced capitalist economies are characterized by economic dualism: their labour markets are divided into primary and secondary sectors. The primary labour market attracts natives. It is characterised by higher wages, security, and prospects for advancement. The secondary labour market is filled with migrant workers. It involves low-skill, low-pay, and low-prestige jobs.

In short, international labour migration is largely demand-based in developed societies. This demand grows out of structural features of developed economies: international wage differentials are neither sufficient nor necessary for migration to occur. Low-level wages in immigrant-receiving societies are not likely to increase if the immigrant supply decreases because they are held down by social and institutional mechanisms (job hierarchies). Low-level wages may fall in response to an increase in labour supply.

World Systems Theory

Within this world system, the international flow of labour moves in the opposite direction to the international flow of goods. International migration grows especially in the context of colonial relations.

According to this theory, international migration can be managed through policies that regulate the globalizing market economy (although this is resisted by multinationals). It can also be regulated through the protection of overseas investments, including the military and political intervention in the political life of developing countries (although this increases the risk of regime change and refugees).

The world-systems theory (Wallerstein 1974), which takes a historical structural approach, stresses the role of disruptions and dislocations in peripheral parts of the world, as a result of colonialism and the capitalist expansion of neoclassical governments and multinationals. It thus takes account of structural factors. Because the capitalist mode of production, culture, and increased military, communication, and transportation linkages cross boundaries, the spread of capitalism has had a substantial impact on migratory difficulties. Land consolidation, new capitalist farming techniques, and manufacturing facilities have resulted in a socially uprooted populace with fewer attachments to their land and a greater propensity for migration.

Capitalist investment fosters changes that create an uprooted, mobile population in peripheral countries while at the same time forging strong material and cultural links with core countries, leading to international migration. International migration is especially likely between past colonial powers and the former colonies because cultural, linguistic, investment, transportation, and communication links were established early. International migration is mostly driven by global economic forces, not by pay disparities between countries..

It illustrates how interactions between different societies can play an essential role in social transformation within societies. Trade with one country that creates an economic downturn in another may provide an incentive to relocate to a country with a more vibrant economy. It can be argued that even after decolonization, the economic dependence of former colonies still remains on mother countries. It can be argued that developed countries import labour-intensive goods, which causes an increase in the employment of unskilled workers in less developed countries, decreasing the outflow of migrant workers. The export of capital-intensive goods from rich countries to poor countries also equalizes income and employment conditions, thus also slowing migration.

Chain Migration

Chain migration is the social process by which immigrants from a particular area follow others from that area to a particular destination. The destination may be in another country or in a new location within the same country. Here a migrant communicates to family and friends at home, encouraging further migration along the same path, along kinship links.

Important aspects of chain migration

1. Social Networks: Migrants rely on the established social networks of their destination country. These networks offer critical aid with housing, employment, and adjusting to a new environment. Social networks lessen the dangers and expenses associated with migration, making it easier for new migrants to settle.
2. Family Reunification: Family reunification is a key component of chain migration. Initial migrants frequently bring immediate family members to the destination country, who may then bring other relatives. Many immigration rules favor family reunification, facilitating chain migration.
3. Information Flow: Migrants share information about employment opportunities, living conditions, and legal requirements with prospective migrants in their native country. This information flow minimizes the perceived risks of moving.
4. Economic and Social Support: Established migrants frequently provide financial aid to newcomers, such as loans or job referrals. Social support, including assistance with cultural adaptation and language learning, is also required.

Implications of Chain Migration

1. Community Formation:

• Chain migration causes the creation of ethnic enclaves or migrant communities in the destination country. These communities promote a sense of belonging and cultural continuity.
• Such enclaves can have both beneficial and negative consequences, including offering support for newcomers while also impeding greater social integration.

2. Sustained Migration Flows:

• Chain migration can result in steady and predictable migration flows throughout time. Once a migration chain is started, it tends to repeat itself as other people from the same location migrate.
• This can have a large demographic and economic impact in both the origin and destination regions.

3. Economic Integration:

• Migrants who arrive via chain migration frequently benefit from established networks, which can hasten their economic integration and upward mobility.
• However, relying on ethnic networks may impede broader labor market integration.

4. Policy Considerations:

• Immigration rules that promote family reunification or community sponsorship can aid with chain migration.
• Policymakers must balance the benefits of chain migration, such as social assistance and integration, with the potential negatives, such as the concentration of migrants in specific places and the strain on existing resources.

Chain migration is a potent process that influences global migration trends. By exploiting social networks and kinship links, it decreases migration costs and risks, enhances newcomer integration, and sustains migratory patterns over time. Understanding chain migration is critical for policymakers to create successful immigration policies that take into account both the benefits and drawbacks of this phenomena.

Zelinsky Model of Migration Mobility Transition

The focus here is on the transition of countries through a series of demographic and societal stages. In the early stages featuring strong demographic growth there is mostly rural-to-urban mobility followed by high net migration towards developed countries. As countries become advanced economies, rural-to-urban mobility shrinks, demographic growth slows down, while urban-to-urban mobility and circular migration increase significantly. Advanced economies often become net importers of low-skilled labourfrom less developed countries.

• Stage one ("Premodern traditional society"): This is before the onset of urbanization, and it is very little to no migration and natural increase rates are about zero. There are very high levels of mobility (nomadism), but very little migration.
• Stage two ("Early transitional society"): During stage two a "massive movement from the countryside to cities" occurs. And as a "community experiences the process of modernization". There is a "rapid rate of natural increase". And Internationally there is a high rate of emigration, although the total population number is still rising.
• Stage three ("Late transitional society"): Stage three corresponds to the "critical rung...of the mobility transition" where urban-to-urban migration surpasses the rural-to-urban migration, where rural-to-urban migration "continues but at waning absolute or relative rates", and "a complex migrational and circular movements within the urban network, from city to city or within a single metropolitan region" increased, circulation and non-economic migration start to emerge. Then the net-out migration trend shifts to a net-in migration trend as more people immigrate than emigrate. That is, more people move in rather than out.
• Stage four ("Advanced society"): During stage four the "movement from the countryside to the city continues but is further reduced in absolute and relative terms, vigorous movement of migrants from city to city and within individual urban agglomerations...especially within a highly elaborated lattice of major and minor metropolises" is observed. A large increase in urban to suburban migration can also occur. There is a "slight to moderate rate of natural increase or none at all".
• Stage five ("Future super-advanced society"): During stage five "Nearly all residential migration may be of the interurban and intraurban variety. No plausible predictions of fertility behavior because of a declining population,...a stable mortality pattern slightly below present levels".

Push-Pull Theory by Lee

Lee’s model of migration suggests there are pull factors and push factors within the origin country and the destination country.

Pull factors are factors that attract a person to move to a new area. Examples include:

• higher wages
• higher standards of living
• higher standards of education
• Freedom
• more job opportunities.

Push factors are factors that force people to move from an area. Examples include:

• War
• Poverty
• Famine
• Conflict
• Fewer job opportunities
• Poor standards of living

Another element of Lee’s model is intervening obstacles. These are factors that can prevent or make it more difficult for a person to migrate to another country. Examples include:

• transport difficulties
• passport and visa requirements
• Strict border controls
• Mountain, Sea, Desert

In recent decades, intervening obstacles may have been reduced for people trying to migrate. Globalization has helped reduce these intervening obstacles. For example, with developments in transport technology, such as aircraft, it takes a much shorter time for people to migrate elsewhere. Additionally, with the increased flow of information through communication websites, potential migrants can communicate with people who have already migrated to another country to gain an insight into their experiences of migration and their life in their new country.

Migration Systems and Network Concepts

This theory focuses on the nexus between people at origin and destination. Migratory movements are often connected to prior long-standing links between sending and receiving countries, like commercial or cultural relationships. These give birth to migration systems, i.e. two or more countries exchanging migrants, and migration networks, such as circular and diaspora-based migrations. People move where they can rely on someone they know. The processes are cumulative and do not necessarily tend to an equilibrium: the more the diaspora expands the more it will attract new migrants.

Institutional Migration

According to this theory, organizations that developed alongside international migration started to play a role in nurturing and encouraging further migration. The imbalance between the scarcity of visas or other legal channels to enter destination countries and the number of people who wish to migrate helped to create a migration economy and a specific market whose actors range from immigration attorneys, and travel and recruitment agencies, to smugglers.

The main focus of institutional migration theory is how different institutions influence migration patterns. It draws attention to the ways in which institutions of society, laws, and organizations either help or impede the migration process. This theory is essential for comprehending how migration is impacted by a variety of institutional structures and behaviors in addition to personal choices and economic variables.

A thorough framework for comprehending how different institutional actors and institutions influence migration is provided by institutional migration theory. It highlights the fact that decisions about migration are not just personal or financial in nature but are heavily impacted by the policies and actions of many levels of institutions. In order to create effective migration policies and programs that balance the interests of host and origin nations while addressing the needs and rights of migrants, it is imperative to acknowledge the role that these institutions play.

Key Components of Institutional Migration Theory

1. Role of Organizations

1. Recruitment Agencies: By assisting in the matching of workers and employers, these organizations promote labor mobility.
2. Non-Governmental Organizations (NGOs): NGOs frequently offer advocacy, social services, and legal assistance to immigrants.
3. Smuggling Networks: In certain situations, especially in areas with stringent immigration laws, unofficial or illegal organizations have a major role in assisting migration.

2. Government and Legal Frameworks

1. Immigration Laws and Policies: National laws specify who is allowed to come into a nation, remain there, and work there. The general pattern of migration is shaped by these laws.
2. International Agreements: Migration patterns and policies are influenced by bilateral and multilateral agreements, such as labor migration treaties and refugee conventions.
3. Border Control and Enforcement: Organizations in charge of maintaining border security have an impact on the movement and circumstances of migrants.

3. Social Institutions: 

1. Family and Kinship Networks: Families, as well as other social institutions, are vital in facilitating migration by sending money home and by offering first housing and employment opportunities.
2. Community Organizations: In the countries of destination, ethnic or community organizations aid in the integration and settlement of recent immigrants.

4. Economical Institutions:

1. Labour Markets: Economic organizations, such as companies and labor unions, have an impact on migration through negotiating working conditions and generating demand for migrant labor.
2. Financial Institutions: By enabling migrants to send money home, banks and remittance services support the economic side of migration.

In addition to the ‘classic’ theories outlined above, experts have progressively stressed the role played by immigration policies. Especially after World War II, international migration has been taking place within an increasingly complex set of national and international policies aimed at regulating and controlling immigration, admissions, and flows.