Which came first - media bias or readership bias?

The Left love to tell us how newspaper bias, driven by the ego and political views of their owners, are affecting the politics and voting of their readership, with particular scorn poured on The Sun and Daily Mail. The right have their targets as well, normally the BBC, but The Guardian is often reviled, but probably not to the same extent the Left hate Murdoch's Sun.

An interesting study has been carried out in the USA and reported in last week's Economist* which provides an answer, and not the one the Left will want to hear, but sadly it can't be used to quieten the Right. I am not going to post the whole thing here, just the conclusion:

First, they measured whether a newspaper’s circulation responded to the match between its slant and its readers’ views. Not surprisingly, they found that more “Republican” newspapers had relatively higher circulations in more “Republican” zip codes. But their calculations of the degree to which circulation responded to political beliefs also allowed them to do something more interesting: to calculate what degree of slant would be most profitable for each newspaper in their sample to adopt, given the political make-up of the market it covered. They compared this profit-maximising slant to their measure of the actual slant of each newspaper’s coverage.

They found a striking congruence between the two. Newspapers tended, on average, to locate themselves neither to the right nor to the left of the level of slant that Mr Gentzkow and Mr Shapiro reckon would maximise their profits. And for good commercial reasons: their model showed that even a minor deviation from this “ideal” level of slant would hurt profits through a sizeable loss of circulation.

Showing that newspapers have a political slant that is economically rational does not necessarily answer the question of whether ownership or demand determines bias. Here, the academics are helped by the fact that large media companies may own several newspapers, often in markets that are politically very different. This allowed them to test whether the slants of newspapers with the same owner were more strongly correlated than those of two newspapers picked at random. They found that this was not so: owners exerted a negligible influence on slant. Readers’ political views explained about a fifth of measured slant, while ownership explained virtually none.

Assuming we can translate this to UK, and I don't see why not, it looks like they have sorted out the chicken and egg conundrum of newspaper bias in this country. It would be nice to think that it will at least put an end to the hard left's bleating about Murdoch being the root cause of the country's ills, but I doubt it.

But what of the Right's claims about BBC bias**? Sadly this study can't be used either way as the BBC does not need to respond to a market, any market, so it cannot be measured and will remain open to the Right's allegations.

*Unfortunately it behind a subscription wall

** FWIW I reckon that at worst the BBC is guilty of group think by people who have never felt the cold wind of competition and so don't really understand markets, rather than any conspiracy.