By Paul Krugman

(FORTUNE Magazine) – There's been a lot of bad news out there in the world economy lately. Supposed economic superpowers like Germany and Japan have fallen on hard times; Asian tigers that thought the future belonged to them suddenly find that it belongs instead to Westerners with ready cash; Latin Americans who thought they had put their past behind them are watching with horror as financial crisis strikes once again. And yet there are also some surprisingly happy economic stories out there. What do they have in common?

The biggest favorable surprise is, of course, the amazing performance of the U.S. economy. But there is Australia as well--smack-dab in the middle of the crisis zone, riding the storm out without pain. (Australia's economy grew nearly 5% over the past year, while neighboring Indonesia's shrank 14%.) There is Ireland, the recently dubbed "Celtic tiger," growing at an amazing 8% rate for the past five years. Then there are the British: They have been suffering a bit of a wobble recently, but the fact remains that not long ago they had the highest unemployment rate among major European countries, and now they have the lowest. Nor should we forget Canada (it's that cold place north of here, with all the female singer-songwriters): While it has lagged behind the U.S., it has strongly outpaced Europe and Japan in growth and job creation.

A lot of effort has gone into figuring out what the world's crisis countries have in common--indeed, the search for "indicators of vulnerability" has become a substantial industry. But what about indicators of invulnerability? What do the countries that have managed to remain prosperous while the world suffers have in common? Well, the answer is plain to the naked eye--or make that the naked ear. Yes, the common denominator of the countries that have done best in this age of dashed expectations is that they are the countries where English is spoken.

As Dave Barry would say, I am not making this up. Statistical analysis suggests that there is a real sense in which the English-speaking economies tend to have a common destiny, even when they seemingly shouldn't. Consider the case of the U.K.--which is, say sensible people, a European nation even if some of its politicians wish it weren't. The U.K. does much more trade with its European neighbors than with its transatlantic cousins. But the U.K. business cycle, it turns out, is highly correlated with that of the U.S. (since 1982 the unemployment rates have had a correlation coefficient of 0.74; a 1.0 means perfectly correlated) and not at all correlated with the new euro zone (correlation coefficient of -0.08!). Australia may be a sheep-raising and mining economy on the other side of the world, but its cycle, too, is remarkably correlated with what happens in the U.S.

So what do the English-speaking countries have in common that might explain why they are all doing relatively well right now? I've done some research--namely, talked to a couple of colleagues over lunch--and come up with the following speculations:

First, there's the Alan Greenspan theory--or is it the Larry Summers theory? Economic policy in English-speaking economies tends to be run by smart economists with one foot in the academic world, who therefore make better decisions than the doctrinaire mandarins who run ministries of finance. And in a world where the rules have suddenly changed, the story goes, clever men and women who went to MIT are better able to adapt than bureaucrats whose only expertise is in office politics.

A slight variant is the Margaret Thatcher theory. In the 1980s there was an ideological groundswell in the English-speaking world in favor of markets and against government intervention; perhaps the rest of the advanced world missed the tide because it couldn't read Milton Friedman in the original.

Then there's the globalization theory. English is the language of the global economy--business must use some lingua franca, and no other tongue has the necessary critical mass. That means people who have grown up speaking English have an automatic head start.

Finally, there's the Internet theory. Not long ago, French President Jacques Chirac lamented that the Internet is an "Anglo-Saxon network"; what he probably meant was "English speaking." And it is, as is the whole new technological universe. One particular point that a friend made to me is that e-mail and the Internet put people who use nonalphabetic writing, like the Japanese, at a particular disadvantage.

On the whole, I'd probably place most of the emphasis on Greenspan and Thatcher. But one thing is clear: Something about the zeitgeist--sorry, I mean the spirit of the time--favors those of us who speak English. Let's enjoy it while it lasts.

PAUL KRUGMAN is a professor of economics at MIT.