The people of Britain will soon be voting in a referendum on Brexit: whether Britain should leave the European Union. Whatever side you support, it is clear that this is an extremely important decision for the future of Britain and Europe. Yet a recent survey by the British polling firm Ipsos MORI finds that most of the British public is ignorant or misinformed about basic facts relevant to the Brexit decision. Here are a few of their findings:

EU immigrants: we massively overestimate how many EU-born people now live in the UK. On average we think EU citizens make up 15% of the total UK population (which would be around 10.5m people), when in reality it’s 5% (around 3.5m people). Those who intend to vote to leave overestimate EU immigration more: they think 20% of the UK population are EU immigrants, compared with the average guess of 10% among those who intend to vote “remain”….

Child Benefit: we massively overestimate the proportion of Child Benefit awards given to families in other European countries. The actual proportion of UK Child Benefit awards going on children living abroad in Europe is 0.3%, but 14% of us think that 30% of UK Child Benefit goes to children abroad and 23% of us think 13% does. This means that nearly 4 in 10 of us think the number of children in EU countries receiving Child Benefit from the UK is 40 to 100 times the actual level…

Inward investment from EU countries: we underestimate how much investment into the UK comes from EU countries. The average guess is that they contribute 30% of total investment into the UK, when it actually makes up almost half (48%). This perception gap is mirrored by an overestimation of investment from China, which people think makes up 19% of inward investment but actually only accounts for 1%.

Overestimation of the number of EU immigrants and the amount of child benefit they get is significant because fear of immigration is one of the main arguments put forward by the “leave” side. Underestimation investment by EU countries in Britain is relevant because one of the main arguments of the “remain” side is that Britain will suffer serious economic harm from leaving the EU (which might well end free trade and investment between Britain and other current EU members).

Significantly, most of the examples of ignorance relevant to Brexit described in the Ipsos MORI poll seem likely to help the “leave” side. If the British vote to leave the EU (particularly if it is by a close margin), ignorance might well have played a decisive role in the outcome.

That doesn’t necessarily mean that a decision to leave would be the wrong choice. While I tentatively conclude that the “remain” forces have the better of this debate, I recognize that it is a genuinely difficult issue, and there are some good arguments for leaving, as well. In Chapter 2 of my book on political ignorance, I describe how there are rare cases where political ignorance has beneficial effects. The Brexit vote could potentially turn out to be one of them. In general, however, public ignorance about this and other important issues usually causes more harm than good.

Sadly, public ignorance about the issues at stake in the Brexit vote is just one part of a much broader problem of large-scale political ignorance in Britain and around the world. Political ignorance is also widespread in the United States, and has already played a significant role in the current presidential election. While British voters are often poorly informed, the same is true of their American counterparts.

Most of that ignorance is not the result of stupidity or of information being unavailable, but is a consequence of rational and understandable behavior by individual voters. But that does not make it any less troubling.

On June 23, Britain faces a fateful decision: whether or not to leave the European Union. And the world will be watching. (Daron Taylor,Jason Aldag,Danielle Kunitz/The Washington Post)