Migration has profoundly shaped the nature of the world we live in and continues to do so today. It is estimated that the number of people who have migrated to live and work in other countries has doubled from 99.8 million in 1980 to 200 million in 2005, though this still represented only 3% of the world’s population (United Nations 2004).

The following section presents a brief overview of different analytical approaches that have been used to understand why people migrate and how they choose the places they migrate to.

• Neoclassical migration models
• New Economics of migration
• Structural approaches to understanding migration
• Contemporary approaches to migration

Neoclassical migration models

In the past many migration theorists constructed “migration models” including those based on Ravenstein’s “Laws of Migration” (1885). These theorists drew up a number of general rules or principles that they claimed applied to all migration. These included assumptions (a) that men are more likely to migrate across national borders than women; and (b) that decisions to migrate are made on the basis of an individual’s assessment of the costs and benefits of their own migration decisions.

In this approach, migration is seen as a decision made by an individual seeking a better life which could include better job opportunities, job security and higher wages. This decision is based on an assessment of the factors which impel people to leave their home country and the factors that draw them to the destination country - the so –called “push and pull” factors. Each migrant is considered to be a rational actor who chooses from a range of destinations, the one that involves the least cost (the travel costs, the cost of living while looking for work, the cost of finding a new home) and gives the most net gain (income). This is called the ‘human capital’ approach. Later models such as those put forward by Stouffer (1940) and Lee (1966) added intervening variables such as obstacles and opportunities encountered during the migration process to the pull-push factors of the earlier model.

These neoclassical models have been criticised for their narrow focus on wage differentials between departure country and receiving country, and on the economic motivations of potential migrants. In fact, economic advantage is not the only motivation for migration and even this cannot be reduced to simple differentials in wages and employment. These models were developed during the industrial-era of migration from Europe to the Americas, Australia and New Zealand.  It is now recognised that they are not adequate to understand the patterns and forms of migration in the later decades of the 20th century and the early 21st century.

To summarise:

• Neoclassical approaches focus on differentials in wages and employment conditions in different countries; and on migration costs and benefits.
• Migration is viewed as an individual decision to maximise income.

New Economics of migration

In what is considered an extension of these early models, this perspective - which emerged in the 1980s - views migration as a decision made by families or groups (Stark 1984). Migration decisions were still considered to be based on an analysis of costs and benefits by a family or a community which seeks to maximise the income and minimise risks such as those resulting from crop failures. This approach has been called the ‘new economics of migration’.

Like the neoclassical models, push-pull factors are used to understand the individual or family’s decision making. One example of such migration would be when a family decides to send one of its members to work in another country and relies on remittances to minimise the risks for the rest of the family.

While these approaches address some of the criticisms of the early neoclassical approaches, they still view migration decisions as based on rational choices made by families.

To summarise:

• New economics of migration views migration as a rational family decision to minimise risks and maximise income.

Structural approaches to understanding migration

Historical-structural explanations shift from an exclusive focus on individual/ family decision-making and consider how structural factors create conditions in which migration takes place.  These structural factors - such as the nature of modern industrial economies which create a demand for particular categories of workers, political factors such as the availability of visas or work permits for certain jobs, and social factors like access to social networks - can be seen as 'pushing' emigrants from their homes and 'pulling' them to their destinations.

One structural explanation is the concept of 'dual labour markets' (Piore, 1979). This term refers to the two types of jobs that exist in a capitalist economy. The first are the secure, permanent high-skilled and well paid jobs. The second are the temporary, unpleasant, low status jobs, which are poorly paid, also known as the 3-D jobs (dirty, dangerous and demanding). These jobs offer few opportunities for progression to better jobs, and are often unprotected by workers’ rights legislation and labour standards. In many cases local workers are not interested in such badly paid jobs, so they are taken up by new migrants.

World systems theory and the world society approach focus on forces operating at a global level. World systems theory sees migration as a natural consequence of economic globalization whereby companies now operate across national boundaries (Wallerstein, 1974). In later approaches to migration, alongside economic factors, cultural factors are also considered very important. For example, people increasingly consume common cultural forms such as music or films and share cultural values across the world, and therefore this cultural globalisation leads people to perceive economic imbalances and they migrate as a consequence.

These structural approaches offer macro-level explanations that focus on employment conditions at the national or global level. They have been criticised for their lack of attention to individuals and their decision-making processes.

To summarise:

• Migration is viewed as the consequence of pull and push factors that are created by the nature of modern industrial economies in an increasing global economy.

Contemporary approaches to migration

These new approaches do not seek to find rules or principles that are applicable to every migration situation, or indeed believe that such explanations are even possible. The complexity of migration from 1970s onwards has led to a greater attention to the contexts within which particular migration decisions are made.

It is no longer assumed that people make rational decisions based on the information they have and on a cost-benefit analysis. At a micro-level, the new approaches involve in-depth studies of particular communities, migrants and their stories - how migrants interact with their environments, how they confront restrictive state policies, and on the differences and similarities between migrants and non-migrants from similar contexts.

But these contemporary approaches also examine migration decisions and processes in the context of larger macro-level factors that constrain and shape individual/family level decisions and actions. They question the neoclassical push-pull explanation that views migration as a way to achieve a balance between the demand and supply of labour in different regions. For example, much of the current migration to Western countries takes place in a context of a need for migrant workers to undertake the 3-D jobs including care work, while the political context is increasingly restrictive towards immigration.

To summarise:

• Contemporary explanations focus on the migrants and their decision-making processes at the micro-level.
• At the same time, they also seek to understand how these decisions are shaped by larger macro-level factors which include political, economic and social structures.