LONDON — So, Singapore was named the happiest country in the Asia-Pacific (Denmark ranked No 1 in the world) on Wednesday, according to a new survey. But what, exactly, goes into finding whether citizens of a particular country are happy, or otherwise, with their lot in life?

In a word, inequality.

The World Happiness Report, based on a global poll conducted by Gallup, found that rising disparities in income, wealth, health and well-being have fuelled political discontent and are strongly associated with unhappiness by respondents.

The happiest nations, which included Iceland, Norway, New Zealand and Australia, were mostly fairly homogeneous nations with strong social safety nets.

At the bottom of the list were mostly poor countries — Burundi finished last, preceded by nations such as Syria, Togo, Afghanistan, Tanzania and Madagascar — many of them destabilised by war and/or disease.

Scholars found that three-quarters of the variation across countries could be explained by six variables: Gross domestic product per capita (the rawest measure of a nation’s wealth); healthy years of life expectancy; social support (having someone to count on in times of trouble); trust (perceived absence of corruption in government and business); perceived freedom to make life choices; and generosity (as measured by donations).

Some scholars find people’s subjective assessments of their well-being to be unreliable, and they prefer objective indicators such economic and health data. The scholars behind the World Happiness Report said they tried to take both types of data into account.

In a chapter on the distribution of happiness around the world, three economists — John Helliwell from the University of British Columbia; Huang Haifang of the University of Alberta; and Shun Wang of the Korea Development Institute — argued against a widely held view that people have a baseline level of contentment and rapidly adapt to changing circumstances.

They noted that people’s evaluations of their lives “differ significantly and systematically among countries”; that within countries, sub-groups differ widely in their levels of happiness; that unemployment and major disabilities have lasting influences on well-being; and that the happiness of migrants approximates that of their new country, instead of their country of origin.

The economists noted that crises can prompt vastly different responses based on the underlying social fabric. In Greece, where the economy began to plummet in 2007, widespread corruption and mistrust were associated with a diminishing sense of happiness.

In contrast, trust and “social capital” were so high in Japan that scholars found, to their surprise, that happiness actually increased in Fukushima after it was devastated by an earthquake and tsunami, because an outpouring of generosity and cooperation contributed to the community’s resilience and rebuilding.

“A crisis imposed on a weak institutional structure can actually further damage the quality of the supporting social fabric if the crisis triggers blame and strife rather than cooperation and repair,” wrote the economists.

Mr Jeffrey Sachs, a Columbia University economist who helped edit the report, forcefully rejected the notion that happiness and freedom — especially when narrowly defined as economic liberty — are interchangeable.

“The libertarian argument that economic freedom should be championed above all other values decisively fails the happiness test: There is no evidence that economic freedom per se is a major direct contributor of human well-being above and beyond what it might contribute towards per-capita income and employment,” he wrote.

“Individual freedom matters for happiness, but among many objectives and values, not to the exclusion of those other considerations.”

THE NEW YORK TIMES