The secret of The Economist's success is wowing America

Now take a look at the circulation. In the first six months of this year it was closing on 1.3 million, with some 700,000 of those sales made in the United States, where its home-grown news magazines, Time and Newsweek, are finding it extremely hard to retain readers.

The Economist simply goes on bucking the trend. Yet it refuses to compromise on its diet of sober analysis, occasionally leavened, it must be said, by the odd example of wit and its trademark attention-grabbing covers. Oddly, the people who are generally most critical of the magazine are those who have read it for a long time. Down the years I've often heard long-time buyers bellyache about the leading articles not being up to much.

They rarely stop buying it though, because, as they usually go on to admit, there is always an article, often two, in every edition that tells them something they didn't know (though they rarely admit it in public, of course).

That is one of the central clues to The Economist's success. It is the magazine that can give its readers the edge by providing information about the world - in economics and politics, about business and trade - that its uniquely up-scale audience feel they must know. It's a magazine that links business people to politicians, a forum that offers them required information about each other in order to help them debate essential issues.

As one of its former editors, Rupert Pennant-Rea, famously put it, The Economist engages with "readers with higher than average incomes, better than average minds but with less average time" to "test their opinions against ours. We try to tell the world about the world, to persuade the expert and reach the amateur, with an injection of opinion and argument". Or, more prosaically, The Economist has both cachet and clout, qualities that transform it from being a mere newspaper - as it likes to call itself - into something quite different, an institution.

Its chief executive, Helen Alexander, attributes its success to the way in which it offers "global perspectives" on stories. Even though "the DNA of the company is in London", she says, "it is a recognition that London itself is a global city". No wonder it has therefore been called the magazine of globalisation.

I often think that the magazine is a little like the BBC World Service, dispensing well-informed reports about what is happening around the globe to the people who need to know or, just possibly, those who think they should know. The difference is that The Economist comes at matters with a strong point a view. It is, genuinely, a viewspaper with a strong commitment to the free market.

In fact, it's a sort of weekly free market hymn book, singing the praises of economic liberalism while also extolling the virtues of liberal social reform. This is music to the ears of the business elites in the major cities of the United States - where sales are growing apace - though I would guess that the social reform message is less welcome in what my American friends call "the fly-over states".

Anyway, The Economist's editor, John Micklethwait, likes to point out that his magazine does not believe in untrammelled markets. It just believes that markets are usually better for us than governments. Again, that's preaching to the converted in the US.

However, the magazine does not purvey a sort of one-note journalism in its articles, none of which, as tradition dictates, carries the writer's name. The lack of bylines has become part of The Economist's brand, a quirk that has become part of its unique selling proposition.

Most importantly, of course, a well-heeled audience attracts advertisers too, helping to boost the revenue beyond the dreams of many rivals.

It was the American showman PT Barnum who once observed: "Nobody ever lost money by underestimating the intelligence of the American public." I rather think The Economist has turned that cynical dictum on its head.