Economics, known as the dismal science, has become increasingly interested in recent years in the question of happiness.
Next year a team headed by a Nobel prize-winning economist plans to launch an index to measure people's happiness, to be established alongside gross domestic product as a critical gauge of a nation's progress.
Daniel Kahneman, the Princeton psychology professor who shared the 2002 Nobel prize for economics, and Alan Krueger, an economics professor at Princeton, have been working on a "national well-being account" which aims to give a more accurate picture of how happy people are than the one conveyed by standard satisfaction questionnaires.
"Happiness economics" is not yet in the economics textbooks but it has edged closer to the mainstream as the link between rising income and happiness has broken down. An accurate measure of well-being has the potential for widespread application in business and government.
Gallup, the US-based pollster and management consultant, is paying top academics such as Prof Kahneman and Ed Diener, professor of psychology at the University of Illinois, who is working on a separate "national well-being index", for advice on how to measure well-being.
Companies have long talked about their employees being their greatest asset. "Now they seem to actually mean it," said Jim Clifton, Gallup's chief executive, who says the company is spending "huge" amounts on research and development on well-being.
"We see this as a big new area that leadership is interested in." He cites the example of a large retailer staffed by employees with low morale. "There will be theft in their stores, more sick days and lower sales. Employers want to know what the impact of well-being on a productive workforce will be," he said.
Governments have also started to take notice. The strategy unit of Britain's Cabinet Office published a paper entitled "Life Satisfaction" in December 2002 in which it argued there was "a case for state intervention to boost life satisfaction".
More recently, in October, the British Treasury hosted a seminar on well-being issues at which Lord Layard, professor of economics at the London School of Economics and author of a forthcoming book on happiness, presented. Hetan Shah, programme director at the New Economics Foundation, a London-based think-tank that supports alternative well-being measures to GDP, said recent government initiatives focusing on issues such as childcare were symptomatic of a change in government thinking.
In the US, Prof Kahneman's research into establishing a national well-being account is partly federal-funded, through the National Institute of Ageing.
Economic output as measured by GDP has risen steeply in recent decades in the developed economies but people have not been getting significantly happier.
If the link between GDP and happiness no longer exists, one of the key objectives of government policy in keeping GDP on an upward trajectory is called into question. This is partly why economists have increasingly turned their attention to the study of happiness, once exclusively the preserve of psychology.
One problem has been devising robust quality-of-life indicators, a subject to which the annual American Economic Association conference devoted its attention in a session on the economics of happiness at the weekend.
Survey data can be erratic, partly because for one person a score of five on a scale of one to 10 when asked how happy they are might equate to seven for someone else. Mood may also influence replies. Prof Kahneman's team believe they have devised a way of getting round such problems by getting people to rank their enjoyment of different activities over a period of time.
Speaking before the conference, held in Philadelphia, Prof Krueger said the team was developing a phone survey version of the national well-being account with Gallup.
"If all goes well, we should be able to implement the method a year from now. I hope it could, years from now, become as important as GDP," he said.
