20 Years of Global #Migration—in One #Chart - Nick Stockton - The Atlantic
▻http://www.theatlantic.com/international/archive/2014/03/20-years-of-global-migration-in-one-chart/359793
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It’s no secret that the world’s population is on the move, but it’s rare to get a glimpse of where that flow is happening. In a study released Friday in Science, a team of geographers used data snapshots to create a broad analysis of global migrations over 20 years.
The study was conducted by three geographic researchers from the Wittgenstein Centre for Demography and Global Human Capital in Vienna. The researchers presented their data in five-year increments, from 1990 to 2010. Their research is unique, because it turned static census counts from over 150 countries into a dynamic flow of human traffic.
Migration data is counted in two ways: Stock and flow. “The stocks are the number of migrants living in a country,” says Nikola Sander, one of the study’s authors. Stock is relatively easy to get—you just count who is in the country at a given point of time. Flow is trickier. It’s the rate of human traffic over time.
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Keeping accurate account of where people are moving has stymied the UN, and researchers and policymakers in general, for a while. The European Union keeps good track of migrant flows, but elsewhere the data are sparse. Static measurements are plentiful, but it is hard to use them to get a picture of how people are moving on a broad scale, because each country has its own methodology for collecting census data.
Last year, however, the UN brought stock data from nearly 200 countries into harmony by erasing the methodological seams between them. To turn this stock data into five-year flow estimates, the researchers used statistical interpolations from stock data from the UN, taken mostly from 10-year country censuses, but supplemented with population registers and other national surveys.
While the results of the migration study aren’t particularly groundbreaking, there are two interesting insights:
Adjusted for population growth, the global migration rate has stayed roughly the same since around 1995 (it was higher from 1990-1995).
It’s not the poorest countries sending people to the richest countries, it’s countries in transition—still poor, but with some education and mobility—that are the highest migratory contributors.
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