U.K. foreign-born population exceeds 8 million

The MO says that one thing worth bearing in mind when thinking about the meaning of these numbers is that both are estimates. They have margins of error and appear in the public domain with a lag, which means that we do not always know precisely when specific landmark numbers are hit. For example, the ONS estimated last quarter’s net migration level at 318,000 plus or minus 44,000, because the survey on which the numbers are based is small and therefore not particularly precise. If the reported number had been 4,000 higher and had thus slightly exceeded the previous 320,000 record, it might have made a bigger news story, but from a statistical perspective the number would be virtually the same.

Similarly, while the U.K.’s foreign-born population is expected to exceed eight million for the first time in the published ONS data, the official statistics take some time to produce, which means that this threshold is actually likely to have been crossed more than a year ago.

In other words, “landmark” moments at which statistical measures reach a certain point are often somewhat arbitrary.

What are the consequences of rising migration?
Even if the statistics come with caveats, the basic message that migration now is higher than it was a few years ago is still valid.

The biggest challenge interpreting these numbers is that there is no optimum size for the U.K.’s population or for the number of migrants who live in the United Kingdom. The MO says that from an economic perspective, immigration brings both costs and benefits and affects different people in different ways, leaving no objective method of deciding what the “right number” of migrants is. Different demographic, economic, and political arguments can be marshalled in favor of either increasing or reducing immigration, and reasonable people will disagree.

David Cameron has described U.K. population growth as “unsustainable,” and in 2012 parliament voted to support a non-binding motion that immigration policies should be used to prevent the U.K. population from exceeding seventy million. By contrast, the Scottish government has an objective of increasing population growth, arguing that rural and coastal communities are not sustainable without it.

Looking at public opinion, polls regularly find that members of the U.K. public feel there are “too many” migrants in the United Kingdom. The proportion of British people concerned about the number of migrants in the country has been broadly consistent for decades, however, and was substantial even during the 1990s when estimated levels of net migration were relatively low. Immigration has become more salient in the eyes of the public over the last twenty years. In August this year, Ipsos Mori’s Issues Index poll recorded the highest ever level of concern about immigration, with 50 percent citing it as one of the most important issues facing the country. Public opinion data, however, does not provide a clear guide to what the “right” level of migration would be, making it hard to identify an optimal number of migrants from a democratic perspective, either.

By way of context, the share of the U.K. population that was born abroad is comparable to that of the other EU-15 countries (countries that were members of the EU before 2004). In 2014, six of these countries had larger foreign-born shares of the population, including Austria, Ireland, and Sweden, while nine had smaller shares, including Italy, Portugal, and Finland. The prevalence of migration in the United Kingdom is therefore by no means unprecedented by European standards. Economic performance and attitudes to migration in those countries have varied widely in recent years and their relationship with immigration numbers is far from straightforward.

Seeing the wood for the trees
When new migration numbers are released, they are often used as a simple metric of the government’s success or failure in managing migration. This has particularly been the case since the 100,000 net migration target was introduced.

These headline statistics can be interesting, but they only provide the narrowest slice of the story. They tell us little about either the positive or negative impacts of migration or the trade-offs involved in policy decisions that affect the numbers. “The more fundamental questions about policy successes and failures are more nuanced,” the MO concludes. “They include how immigration affects the U.K. labor market, whether it makes existing U.K. residents wealthier, how different groups of newcomers are integrating, how immigration is perceived in local communities, and how policies at the local and national level affect the impacts of immigration and the U.K.’s ability to accommodate the levels of migration it receives.

“These things are harder to convey in a single number.”