In the Times, David Aaronovitch says the media's promotion of the MMR scare was "a crime worse than phone hacking." This poses a question: did this happen because of the nature of the media, or despite it?

What I mean is that there are two sorts of professional failings. Some are a shortcoming from recognised standards whilst others arise from the values of the profession itself - what the French call deformation professionelle.For example, if a policeman takes a bribe, he commits the former error, but if he is over-zealous in arresting a violent suspect he commits the latter. I suspect that phone-hacking was an example of the latter, as it was motivated by the professional urge to get stories. And I suspect reporting of the MMR-autism link was too. I mean this in three ways:

First, good journalism is not about reporting the "overwhelming scientific consensus", nor even about reporting dry statistics. It's about getting the human interest story. So "my son had the jab and now he's got autism" is a better story than "correlation between MMR jab and autism prevalence is approximately zero."

Secondly, many journalists are employed by capitalists who are trying - with limited success - to make a profit. And there's a tension between what's true and what sells. There's a reason why OK! magazine sells almost five times as many copies as the New Scientist. People want gossip, sensationalism and human interest stories, not dry statistical analysis. And it's the job of employees in capitalist companies to give the customers what they want. (Yes, I know I sometimes try to provide statistics in my day job - but I'm an absolutely crap journalist with very few readers.)

Thirdly, David complains about BBC editors who "thought that you could balance a health spokesman with a campaigner, call it a 'controversy' and somehow do your job of informing the public." But this pursuit of "balance" is a longstanding aspect of a strand of "serious" journalism. It was satirized by Alexander Cockburn back in 1982 - "should cannibalism be regulated?" - and we hear it every day on Today and the PM programme. And it can be misleading. To take just two examples, the rough consensus amongst economists (there are exceptions, of course, and consensuses can be wrong) is that immigration controls and fiscal austerity are bad ideas. Not only do you not get this impression from the right-wing press - which is only to be expected - but you don't always get it from the BBC, because of its commitment to "balance" rather than truth.

A large part of the BBC's job is to try not to offend noisy or powerful interest groups. You can't achieve that without some jeopardy to the truth.

What I'm saying here is what I said the other day - that there is a distinction between the news and a good story on the one hand, and the truth on the other. Sometimes, the distinction is very sharp indeed.