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3.2: Definitions and Data

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    Migration can be interregional (between regions), intraregional (within a region), or international (across national borders). Those moving in are immigrants, and those moving out are emigrants. Net migration is the difference between the number of immigrants and the number of emigrants in any given year. The United Nations provides data and analysis on immigration and emigration annually, but such figures depend largely upon government sources that are more reliable in some cases than in others. For example, the United States (US) maintains databases on immigrants of all types including guest workers (those given permission to enter the country legally for a specific job and for a specific period of time), students, tourists, asylum seekers (those seeking sanctuary from political, religious, gender, or ethnic persecution), and undocumented migrants (those inside of a country without proof of residency). However, the US does not maintain or report data on those that have emigrated, except in those notable cases where individuals have denounced citizenship. Meanwhile, countries like Mexico and the Philippines track their overseas citizens regularly, acknowledging the realities of dual citizenship or residency. Return migration (a permanent return to the country of origin) also represents a significant flow of people, but is often under- reported. For example, up to one quarter of Europeans that migrated to the US in the late nineteenth century eventually returned to Europe. In recent years, more people have migrated back to Mexico from the US than from Mexico to the US. The process of migration, then, is a complicated nexus of movement rather than a simple one-way, permanent, single-directional move from place A to place B.

    In spite of the complex patterns and processes of migration, some general characteristics of migration and migrants were articulated by British demographer Ernst Ravenstein (1885), characteristics known as the laws of migration. Many of them still hold true 135 years later. Can you decide which are still true today?

    1. Most move only a short distance.
    2. Each migration flow produces a counter-flow of migrants.
    3. Long-distance migrants tend to move to major cities.
    4. Rural residents are more migratory than those in towns.
    5. Females are more migratory than males.
    6. Economic factors are the main reason for migration.

    In short, each of the “laws” generally hold true in 2018 with the notable exception of number five. Slightly more men moved internationally than women, but the truth is much more complicated. In fact, Ravenstein’s estimates of female migration proved incorrect as large-scale migration to North America increased in the early twentieth century, during which time most immigrants were men seeking land, wealth, and opportunity in the “New World.”

    A variety of non-government organizations, research groups, and humanitarian entities also track the movement of people across borders and within countries in order to provide a deeper understanding of the causes and effects of migration locally, regionally, nationally, and globally. For example, the Migration Information Source ( offers a wealth of reports, analysis, and data visualization that dramatically enhance our geographic understanding of migration. The Pew Research Center ( conducts regular polls often focused on Latino populations in the US. Other non-profit organizations track the effects of immigration in the US and publish regular reports, but often they lack objectivity or editorial oversight, as the intent of such efforts is to achieve policy change to reduce immigration levels. For example, the Federation for American Immigration-FAIR (fairus. org) is an organization motivated by the explicit desire to reduce the number of immigrants and to secure the traditional cultural heritage of European Americans.Likewise, the Center for Immigration Studies (CIS) presents data to support its stated vision “of an America that admits fewer immigrants” and to reduce immigration of all kinds in the twentieth century ( Immigration-Studies).

    Geographers have identified general trends in global migration, also known as North-South migration, in which most emigrants originate in poorer, developing countries and most destinations have traditionally been wealthier, developed countries. For most Americans and Canadians, this pattern is very familiar, as recent decades have seen unprecedented numbers of Latinos immigrate to the US for the purpose of finding higher-paying jobs and better opportunities and escaping structural poverty in the developing world. Similarly, the recent patterns in Europe have seen record numbers of Eastern Europeans move west and north to earn higher wages than those available in the home country. However, such wage differentials do not tell the whole story. For example, wages in Chicago tend to be much higher than those in other parts of Illinois, but not everybody leaves rural Illinois just because they can earn a higher wage. Wages, though significant, only tell part of the story. Unless you are reading this text in Manhattan or Paris or Hong Kong, you could most likely move tomorrow and find a job elsewhere that pays more than what you earn now (if you are working). Geographers recognize that attachment to place, cultural factors, desire to stay close to family/friends, and other factors play a powerful role in the decision to move or stay.

    Another pattern that has remained consistent over time is that of highly skilled migrants, who tend to enjoy a much greater freedom of movement than those with lower levels of education and fewer skills. For example, computer software engineers, database managers, and a host of other highly-demanded skills lead to efforts by countries and corporations to attract the best and the brightest minds to immigrate in order to bring those skillsets into a country where they are in short supply. Countries often offer travel visas (temporary permission to enter a country) to those with highly demanded skillsets. Countries like Australia, Canada, and New Zealand utilize a points system to determine which of the highly-skilled applicants will be granted permission to enter. The brain drain refers to the conceptual idea that when a wealthy country recruits the ‘best brains’ from a poorer country, it can be damaging to the sending country, as many of the most qualified and talented groups of people are poached away by higher-payingopportunities. As such, the term brain gain refers to the benefits received by a country that receives all those “brains” without having to produce them from scratch! Recently, countries have also acknowledged the concept of brain waste, in which receiving countries fall short in utilizing the full range of human capital inherent in many immigrant populations. For example, nearly half of all immigrants into the US from 2011-2015 held at least a bachelor’s degree, but more than 2 million immigrants with college degrees continue to work low-skilled jobs because employers or governments do not recognize foreign-held degrees. Similarly, a brain-drain/brain-gain phenomenon occurs within some countries, such as the US. California and New York, for example, continue to draw the most highly-trained and qualified people away from other states. Governments that wish to keep the highly skilled at home take such transfers of educated and highly- skilled people very seriously.

    Framing migration as a loss or gain, however, also does not tell the whole story. Most countries that send migrants also receive them. The US receives large numbers of immigrants, but it also is a country of emigration, whereby retirees choose to live outside of the US, or long-term migrants (who usually are US citizens) choose to return to their home country in retirement. Migration is neither inherently good nor bad; rather, it is complicated. This chapter seeks to tease out some (but not all) of the important characteristics of migration in the twenty-first century to help you gain a better understanding of a topic that too often is used by politicians to gain votes or credibility. Let us put those simplistic debates aside for a few minutes to consider the basic elements of migration around the world.

    3.2: Definitions and Data is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by David Dorrel & Joseph P. Henderson (University of North Georgia Press) via source content that was edited to conform to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.