Is life getting better or worse as you grow older?

Robert F. Kennedy once said that GDP, or gross domestic product, "measures everything ... except that which makes life worthwhile."

GDP, in case you weren't paying attention in Econ 101, looks at economic activity as a way to size up how a country is doing.

RFK has a point. The status of a country amounts to more than the number of goods it produces and sells. Psychology professor Arthur Stone says, "Right now, there's a lot of dissatisfaction in using GDP as a measure of a country's progress."

So then what do you use?

For several years now, scientists have been grappling with this question. A study published this week in The Lancet uses levels of personal satisfaction to examine global well-being. Stone is one of the study's authors — and the director of the University of Southern California's Dornsife Center for Self-Report Science.

Researchers examined data from the Gallup World Poll and the English Longitudinal Study of Aging, both of which poll residents about their lives. About 1,000 people in 160 countries were asked how satisfied they were; how they'd rate their moods, such as happiness, sadness and anger; and their judgments about the meaning and purpose of their lives.

"Well-being includes objective circumstances, like safety, money and health, but also subjective things like how people feel about their lives," says Stone.

In wealthy countries like the U.S., Australia, Canada, Ireland and the United Kingdom, people report the lowest level of satisfaction during their middle years, starting at about age 45. Then at about age 54, they start reporting less stress, anger and worry. Their reported levels of happiness and satisfaction only increase thereafter, into old age.

But in countries facing economic (as well as political) struggles — in the former Soviet Union, Eastern Europe, Latin America and sub-Saharan Africa — people grow less satisfied as they get older. People report sharp declines in life satisfaction in middle age and continuing into old age. And people in sub-Saharan Africa report low levels of satisfaction as youngsters — and things never get better.

While data from the study can't say why that is, it's possible to speculate from some of the interviews that poverty, poor health and substandard housing are factors. (So maybe GDP does have something to do with satisfaction after all.)

Perhaps the relentless downward slope in some of the countries reflects "political changes like the fall of communism," Stone says. But he adds: "We can't say exactly why that is. We don't have all of that data. But this really pushes for more research."

Poor health is connected to lower life satisfaction in the survey data. It could be a two-way street: Poor health might lead to lower rates of happiness while lower satisfaction with life contributes to poor health. But those relationships need more research, says Stone: "It's an interesting question. As you age, life satisfaction is improving for many people, but when you get to a point where you're really ill, satisfaction numbers go to hell."

There is a perception in the U.S. that people in other countries treat elders better than Americans do. "This [study] flies in the face of what we think," Stone says. "In the U.S., the person on the street would say older people are not respected much here. In other countries, families may respect elders, but some social systems do not." Copyright 2019 NPR. To see more, visit https://www.npr.org.