Last year's study showed that whereas rich people are happier on average than poor people, increasing GDP in a country doesn't necessarily boost well-being. For instance, GDP tripled in the United States since the 1960s, yet well-being has stagnated.

"There is now a rising worldwide demand that policy be more closely aligned with what really matters to people as they themselves characterize their well-being," said study co-author Jeffery Sachs, director of the Earth Institute at Columbia University, in a statement. "More and more world leaders are talking about the importance of well-being as a guide for their nations and the world. The World Happiness Report 2013 offers rich evidence that the systematic measurement and analysis of happiness can teach us a lot about ways to improve the world's well-being and sustainable development."

Happy citizens also make for better countries: The report found that happiness makes fore people who live longer, more productive lives, have higher earnings and are better citizens.

One of the things that intrigued the social scientists is the way Scandinavian countries have consistently topped the Prosperity Index since it began four years ago. That suggests that the Scandinavian countries -- which indisputably have large GDPs -- might hold the key to understanding what conditions in addition to wealth must be present for people to report a high sense of well-being.

Some of the conditions might seem obvious. For example: good health care, good education, and good safety and security. So, too, might economic opportunity and the freedom to start one's own business in an environment free from predatory officials and corruption.

But other conditions that lead people to report they feel their life is worthwhile might be less self-evident. And those are often the very same ones that authoritarian regimes claim are unimportant or which they themselves undermine.

Those things include enjoying the personal freedom to speak, read, vote, and worship as you want. And they include enjoying a sense of social trust -- that is, a sense that those around you trust in the society and are themselves trustworthy.