Of all the phrases bestowed to us by the Founding Fathers, few come up more than “pursuit of happiness.” Yet who knows where the nation really stands on that score?

Now an answer may be forthcoming. Amid a wave of research on the subject, the federal government is seeking ways to measure what some have called gross national happiness.

Funded by the U.S. Department of Health and Human Services, a panel of experts in psychology and economics, including Nobel laureate Daniel Kahneman, began convening in December to try to define reliable measures of “subjective well-being.” If successful, these could become official statistics.

The idea of the government tallying personal feelings might seem frivolous — or impossibly difficult. For decades, after all, the world has gotten by with gauging a nation’s quality of life on the basis of its GDP, or gross domestic product, the sum of its economic output.

But economists and others have long recognized that GDP, a dollars and cents measure, doesn’t count everything that might be considered important when assessing living conditions.

“Our gross national product, if we should judge America by that, counts air pollution and cigarette advertising, and ambulances to clear our highways of carnage . . .it measures everything, in short, except that which makes life worthwhile,” Robert Kennedy said in a 1968 speech.

But as the United States ventures into the squishy realm of feelings, statisticians will first have to define happiness and then how to measure it. Neither is a trivial matter. There is even some doubt whether people, when polled, can accurately say whether they are happy.

“I’m worried about the word ‘happiness’,” Kahneman, an author and psychologist, said during a break in a meeting last week.

Whatever the obstacles, the effort has momentum. President Obama has “welcomed” the effort, according to a White House release, and his chief economic adviser, Alan Krueger, is one of the leading researchers in the field.

Before being named chair of the Council of Economic Advisers, Krueger co-wrote one of the key papers on the topic. In it, Krueger and his co-authors proposed a method for generating a national statistic covering “the flow of emotional experience during daily activities.”

The panel, organized by the nonprofit National Academies, has already met with two of the key figures in the U.S. statistical bureaucracy:Robert Groves, the director of the U.S. Census Bureau, and Steve Landefeld, the director of the Bureau of Economic Analysis, the federal agency that puts out the gross domestic product figures.

According to proponents, a measure of happiness could help assess the success or failure of a range of government policies. It could gauge the virtues of a health benefit or establish whether education has more value than simply higher incomes. It might also detect extremes of inequality or imbalances in how people divide their time between work and leisure.

“The phrase ‘pursuit of happiness’ is in the Declaration of Independence, so it’s not a huge stretch to say we might want to measure life satisfaction,” said panel member Carol Graham, a senior fellow at the Brookings Institution and the author of a book on the topic.

As odd as it may sound, the U.S. effort follows a spate of high-profile efforts by other governments.

In Britain, Prime Minister David Cameron has embraced the idea, and last year the government began asking survey respondents things like “Overall, how happy did you feel yesterday?” and “Overall, how satisfied are you with your life nowadays?” The U.K. Economic and Social Research Council is also funding the U.S. panel’s $370,000 budget. In France, President Nicolas Sarkozy in 2008 launched a commission including two Nobel winners, Joseph Stiglitz and Amartya Sen, which opined that the “time is ripe for our measurement system to shift emphasis from measuring economic production to measuring people’s well-being.”

Far ahead in such measures, however, is the tiny Himalayan kingdom of Bhutan, which has embraced the notion of “Gross National Happiness” as a national goal and has created a commission to achieve it.

“There has been a lot of momentum,” said Arthur Stone, chair of the U.S. panel, and a distinguished professor in the psychiatry department at Stony Brook University. “It’s kind of a snowball.”

When talking about measuring happiness, researchers make what they say is a critical distinction between two ways that people feel happy. There is “experiential well-being,” or how a person feels about their daily activities, and then there is “life satisfaction,” or how people remember and judge their lives or parts of it.

To explain the difference, Kahneman tells the story of a man he met who was listening to a recording of a beautiful symphony — until it ended in a horrible screech.

The man quite emotionally told Kahneman that the screeching “ruined the whole experience.”

But Kahneman notes that it really hadn’t.

“What it had ruined was the memory of the experience,” Kahneman said during a 2010 lecture. “He had had the experience. He had had 20 minutes of glorious music.”

As he puts it, there are two aspects of happiness — one sensed by the “experiencing self” and the other “the remembering self who maintains the story of our lives.”

Researchers believe it is relatively straightforward to gauge the more reflective aspect of happiness, which is often referred to as “life satisfaction.” Surveys can simply ask people, “Generally speaking, how satisfied are you with your life?”

One problem, however, was discovered when Gallup, which has been tracking well-being, found that asking political questions before asking about well-being significantly depresses the life satisfaction score. Gallup has adjusted their methods, but the susceptibility of answers to vary with context has raised questions about the reliability of such measures.

“In a world of bread and circuses, measures like happiness that are sensitive to short-term ephemera, and that are affected more by the arrival of St. Valentine’s Day than to a doubling of unemployment, are measures that pick up the circuses but miss the bread,” wrote Angus Deaton, a Princeton economics professor in a paper studying the fluctuations in the Gallup index.

Measuring the other aspect of happiness, or experiential well-being, meanwhile, also poses logistical problems. It can be cumbersome and costly to track a person’s feelings across a day’s time. For example, when researchers have gauged this kind of well-being, they have sometimes given subjects an electronic device. When signaled by the device, the subjects are required to report their activities and feelings. Other times researchers have asked people to record their feelings in diaries.

Even if happiness can be measured accurately, some statisticians wonder whether it will reveal much more than the GDP figure does — after all, income and life satisfaction often appear to be closely correlated.

A 2010 paper by three researchers from the Wharton School, Daniel W. Sacks, Betsey Stevenson and Justin Wolfers, showed that life satisfaction scores tend to be higher in countries with higher per capita GDPs and that this contentment grows along with the GDP figure.

“We demonstrate that richer individuals are more satisfied with their lives, and that this finding holds across 140 countries, and several datasets,” they wrote. “Across each of these countries, the relationship between income and satisfaction is remarkably similar.”

Similarly, researches have found that experiential happiness rises with income, though only up to the point where income rises to $75,000. After that, “experiential happiness” ceases to rise much.

Still, the correlation between income and happiness, while generally strong, is far from pure. There are outliers. For example, per capita GDP in the United States is roughly six times that of Panama, according to International Monetary Fund figures. But in the most recent 2010 Gallup measure of life satisfaction, the U.S. ranked 12th in the world, one behind Panama.

Landefeld, director of the Bureau of Economic Analysis, said in an interview that he’s skeptical of measurements of subjective well-being, in part because it’s not clear what exactly is being measured and whether such measures move in response to government policy.

“It’s important for us to be relevant,” he said. But “my concern is how would you use it?”