I suspect that Owen Jones gets even more abuse when he's right than when he's wrong. So it has been with his claim that national newspapers and broadcasters are "full of people who made it because of connections and/or personal background rather than merit."

This is true. As he points out, there's lots (pdf) of evidence (pdf) that columnists and top journalists are disproportionately from posh backgrounds. Of course, some of these have merit. But the fact is that background does matter.

Owen gives some reasons for this: the decline of local newspapers as a stepping stone for talented journalists from poor backgrounds; the reliance on internships which are (mostly) only accessible to those from rich families; and the sheer expense of living in London.

I want to add something, though. It's that there are strong economic mechanisms whereby even well-meaning senior journalists might prefer to hire people from posh backgrounds.

They need people they can trust - to file reports on time, spell names right and avoid libel actions; they do not want to have to rewrite copy moments before deadline. And who are they most likely to trust? It's people they know - not necessarily family and friends (though as Owen says that happens), but those who have been working as interns. That's one bias to posh applicants. Failing that, they'll hire those like themselves: we're more inclined to trust people who look and sound like us (affinity fraudsters trade on this). Again, this creates a bias to the posh.

Now, there's nothing unique to the media here. Like hires like in any occupation, simply because it's a way of mitigating the principal-agent problem.

It's for this reason that the fact that MI5 used to vet BBC employees matters even today. The men who were selected as "sound" in the 70s and 80s hired the senior people who work there today. And they are likely to have had a bias towards people like themselves - "sound" people. Path dependence thus generates a bias against subversives even if overt vetting has ended.

There's something else - overconfidence. People from posh backgrounds are more likely to be confident and overconfident than those from poorer ones (the correlation isn't one, but it's greater than zero). We all know that overconfident people are more likely to be hired because hirers mistake overconfidence for actual ability.

And this might be perfectly sensible, as Jung Hoon Lee and Shyam Venkatesan point out in a new paper. Overconfident people, they say, are more likely to work hard because they believe doing so will pay off. And these are the sort of people you want. The posh boy who thinks he can become editor (not least because posh boys do) might well work hard in junior jobs in order to get there. As Arsene Wenger said, "if you do not believe you can do it then you have no chance at all."

On the other hand, whereas some poor kids do have a hunger for success, others lose motivation when they realize they can pay the bills (I know: I'm one). This creates a double selection against such people: they might not get hired in the first place, and even if they do they might stop climbing the greasy pole. Posh people will then be disproportionately in top jobs because those from poorer backgrounds have dropped out: this is perhaps even more true in finance and law than in the media. And because like hires like, so this pattern perpetuates itself.

My point here is that journalism looks like a closed shop not just because bad people hire their mates, but because rational people make rational decisions. This is consistent with the fact that even "liberal" employers such as the Guardian and the art world are biased towards posh white people.

All this is to mostly agree with Owen. Journalism (of the sort he's discussing) is disproportionately populated by posh people, and this massively distorts political debate. I fear, however, that it is very difficult to change this. Perhaps our best hope is simply that the mainstream media continues to decline.