Here’s why Migration Watch got their study on post-Brexit immigration wrong

“Post-Brexit visa proposals could well lead to record levels of immigration”

Migration Watch UK press release, 13 February 2019

Early this morning the Migration Watch think tank published a study claiming    that the government’s plans for Brexit could see immigration increase by about 100,000 people a year. They were talking about ‘net migration’; how many more people immigrate to the UK than emigrate abroad over the course of a year, currently estimated at 273,000. Their study, which was widely covered in the press, estimated this could rise to around 380,000 after Brexit.

However, just a few hours later, Migration Watch unexpectedly issued a press release saying it was withdrawing the paper:

“We have decided to withdraw the paper issued today on post-Brexit migration levels. There was an error in the calculations which was unfortunately overlooked at the final stages of preparation. We apologise for the error and will rectify it in the course of producing a revised version.”

We have the original report, and have spent the day looking into their claims. Here are some key areas where we think they went wrong.  

What the numbers are based on

Migration Watch says its estimates are based on the predicted effects of the government’s White Paper on immigration, published in December last year. That document outlines the government’s plans for a new immigration system once the UK leaves the EU, ending the free movement of EU immigrants across the border.

Migration Watch’s estimates show net migration from both EU and non-EU countries increasing after Brexit, with the huge bulk of that coming from a 100,000 increase in non-EU net migration.

Most of the 100,000 increase is based on the assumption that, after Brexit, there would be a lower salary threshold for certain workers to come to the UK. At the moment, there’s a minimum salary of £30,000 for workers to get a Tier 2 Visa into the UK (with some exceptions). Migration Watch speculates that if that threshold dropped to £21,000, it would mean a large increase in non-EU immigration to the UK.

There's one problem with this assumption, however: that change isn’t something the government actually proposed in its White Paper.

The study overestimates immigration by looking at total visas granted

But that’s not the main issue with the study. To estimate non-EU immigration, it uses visa figures to estimate future levels. But these can’t be used to estimate immigration.

An immigrant is usually defined as someone who comes to the UK to live here for a least a year. If they leave beforehand, they’re just considered a ‘short-term’ immigrant, or a visitor. All of the figures you tend to see about “net migration” use this longer term definition of immigration.

Visa figures won’t just include people who are long-term immigrants – it will include people who just come for the short-term, and it will even include people who get a visa but never end up coming to the UK at all.

So visa figures far exceed actual levels of estimated immigration to the UK.

Migration Watch uses a figure of 456,000 a year for the number of visas granted. But the equivalent figures put actual non-EU long-term immigration over that period at closer to 290,000. That suggests a serious overestimation of the future level of non-EU immigration into the UK.

Official immigration estimates aren’t perfect, and have been subject to legitimate scrutiny in recent years over their accuracy. Nonetheless, Migration Watch’s study is conflating estimates from both sources, comparing a figure based on visa grants to one based on official immigration estimates.

The estimates are based on proposals the government hasn’t made yet

Migration Watch says its estimate could happen “if the proposals in the White Paper become the basis of our future immigration system”. But as we’ve noted, its estimate isn’t actually based on what those proposals said.

The main driver of Migration Watch’s estimate is a large increase in the number of workers coming on a Tier 2 visa, due to lowering the minimum salary threshold for that from the current £30,000 to £21,000 a year.

But the government hasn’t proposed lowering the threshold to this level. It has hinted that it may want to lower the £30,000 in some circumstances , but hasn’t committed to how far this reduction would go. According to the government:

“For intermediate skills, the Migration Advisory Committee recommends keeping the current minimum salary threshold of £30,000. The Government believes that in some circumstances – for example where skills are in shortage—there should be some flexibility to allow migration at lower salary levels…

“before confirming the level of a future salary threshold we will want to engage extensively with businesses and employers, consider wider evidence of the impact on the economy, and take into account current pay levels in the UK economy…”

Migration Watch acknowledges in its study that the threshold is still under discussion, but this uncertainty isn’t translated into its headline claims.

The Home Office told us in a statement:

“These remarks [from the Migration Watch report] are inaccurate and untrue.

“Skilled workers will be required to meet a minimum salary threshold, which the Migration Advisory Committee recommend should be set at £30,000. We will be engaging with business on this, but this it ensures we can attract the talented people we need for the UK to prosper while controlling immigration.”