It's easy to find an online test that will purportedly tell you how happy you are. But how happy are the people of an entire nation? And which nation's people are happiest?

That's hard to measure. So for decades world organizations like the United Nations that concern themselves with improving people's well-being have used a single proxy for happiness: gross domestic product, or GDP. The loose logic is that as people attain a higher standard of living, they will feel less burdened by basic survival and have greater means for everything from decent food to recreation.

But new research indicates that two other factors are even better predictors of a nation's well-being: According to Roly Russell, an interdisciplinary scientist at the Sandhill Institute for Sustainability and Complexity in Grand Forks, British Columbia, a nation's human capital (social structures) and natural capital (nature) are more influential in determining happiness than financial capital (income). Russell presented his data over the weekend at the annual American Association for the Advancement of Science conference in Vancouver.

Russell studied numerous studies about happiness in many nations, assessing 248 variables that the various investigations had relied on. The variables ultimately fell into three broad groups of factors: financial and infrastructure (traits such as GDP and gross domestic savings); human and social (years of schooling, freedom of choice); and natural (health of land on which people live, access to nature). He then correlated those factors with the degree to which people said they were happy. Preliminary results indicated that financial factors reflected only about half the variability in happiness across countries, but human and natural capital each accounted for about two thirds of the difference.

Costa Rica had the highest score for life satisfaction among the 123 countries that were represented, even though its GDP is in the world's lowest third. The single leading factor determining people's happiness there was a strong social support network.

As countries try to set policies to improve well-being, Russell concluded, they have to get away from using just GDP as the de facto predictor. "We can expand our vision of 'development' as more than just improving GDP," he noted. Although measuring factors such as human and natural capital can be difficult, he added, "What's difficult to count may be the most important. The path to becoming a happy country might well involve greater focus on maintaining or promoting healthy natural and social systems, and less on simply producing more 'stuff.'"

To hear Russell explain his conclusions and why Costa Ricans win the happiness stakes, listen to our exclusive podcast with him.

And yes, if you want to test your own happiness and compare it with results from the U.S. and other countries, you can take our quiz.

Photo of happy girl in Costa Rica courtesy of canonsnapper on Flickr