Forget investment and savings rates, worker productivity and wage scales to determine which countries will become richer or poorer. What really stimulates economic growth is whether you believe in an afterlife -- especially hell.
At least that's what two Harvard scholars have found after analyzing data collected in 59 countries between 1981 and 1999.
"Our central perspective is that religion affects economic outcomes mainly by fostering religious beliefs that influence individual traits such as honesty, work ethic, thrift and openness to strangers," the researchers, Robert Barro and Rachel McCleary, wrote in the October issue of American Sociological Review. They also happen to be married.
"For example, beliefs in heaven and hell might affect those traits by creating perceived rewards and punishments that relate to `good' and `bad' lifetime behavior," they wrote.
The data comes from six international surveys, including ones by Gallup, the World Bank and researchers at the University of Michigan. They include questions about attendance in places of worship and religious beliefs. There were four measures of economic development: per capita GDP, educational attainment by adults, the urbanization rate and life expectancy.
Oddly enough, the research also showed that at a certain point, increases in church, mosque and synagogue attendance tended to depress economic growth. Barro, a renowned economist, and McCleary, a lecturer in Harvard's government department, theorized that larger attendance figures could mean that religious institutions were using up a disproportionate share of resources.
"It's all been rather surprising," McCleary said."People didn't believe you could quantify aspects of religion. We wanted to be intellectually provocative. We see about five more years of study to get out all the stuff we want. We're trying to raise interesting questions in a different way."
Since the German sociologist Max Weber wrote about the Protestant work ethic and the spirit of capitalism, social scientists have argued that culture -- including religious habits -- is part of the complex mix that determines a country's economic health. What distinguishes the work of Barro and McCleary, some scholars said, is that it uses a sophisticated analysis of a huge set of data to quantify the arguments of anthropologists, sociologists and political scientists.
"The study's important less for what they found than that they looked," said Mark Chaves, a professor of sociology at the University of Arizona, in Tucson. "They are not the first to look at this but they are the first to look at this as systemically and as rigorously as they have. For forever, people have been saying that culture matters in analyzing economies."
"I think this is a new beginning for the rigorous relationship between religion and economic development, " added Chaves, whose forthcoming book examines how religious congregations influence politics and culture. "They've given us a data set and some tools to examine this in a new way."
One of the motivations for undertaking the study, McCleary said, was that empirical research on economic growth typically neglected the influence of religion.
The research team also wants to look at how religion affects other political and social issues like democracy, the rule of law, fertility and health. At the moment, they have a paper on government and the regulation of religion that is under review by the American Journal of Sociology at the University of Chicago on government and the regulation of religion.
Some of their findings, which have been written about in The Economist and The Christian Science Monitor, first appeared in 2002 as a paper for the National Bureau of Economic Research.
As the couple began their study, McCleary said, it was clear that the widely discussed secularization thesis -- the idea that a country becomes more secular as it becomes richer and more industrialized -- did not apply to the US, one of the most religious nations in the world.
And over the last 30 years, many East Asian countries, including Malaysia, Singapore and South Korea, have experienced both rapid economic growth and the spread of Christianity, Barro said.
"South Korea is a good example of that rapid growth and more religion," he said. There the number of converts from Confucianism and other Eastern religions to Christianity is growing rapidly, he explained.
Some of the lowest levels of religiosity were found in China and North Korea. The lowest levels of economic growth were in sub-Saharan African countries. The former East Germany (which includes Weber's birthplace) was one of the lowest in both religiosity and growth.
But one of the major challenges to such research is that countries that vary in their religious beliefs and practices also vary in ways that have nothing to do with religion, said Paola Sapienza, a professor of finance at Northwestern University.
"Are you really picking up religion or something that correlates with it, like certain laws or social and economic institutions?" she asked.
Last year, in the Journal of Monetary Economics, Sapienza and her colleague Luigi Zingales at the University of Chicago, and Luigi Guiso, of the University of Sassari in Rome, published a paper that did not compare countries but looked at the relationship between religious beliefs and the attitudes shown to foster economic growth.
"On average," they wrote, "religious beliefs are associated with good economic attitudes, where good is defined as conducive to higher per capita income."
But that study found that more religious people were also less tolerant of other races and nationalities and had more negative attitudes toward women. The study based its findings on World Values Surveys data collected at the University of Michigan.
Barro and McCleary also used data from the World Values Surveys, which Ronald Inglehart, a political scientist at the University of Michigan, has been taking for more than 20 years. His surveys of 78 countries show strong links between widespread public values and beliefs, or political culture, and motivation to work, sexual and religious norms and the presence or absence of democratic institutions.
"I find that belief factors play a major role in economic growth, but here is one of the world's leading economists saying so," Inglehart said, referring to Barro. "When Weber argued that big breakthroughs in economic growth were in Protestant countries, it was at a time when many cultures were shaped by Protestant institutions. His notion in the broadest sense is that belief factors play a role in economic factors."
"This is a revised view of the Protestant ethic," he continued. He noted that many mostly Protestant, wealthy countries were now more interested in quality of life, and that many Eastern countries were now more focused on economic growth -- with some populations even converting, as Barro noted, to Christianity and specifically to Protestantism.
"Confucian countries are now the most Protestant countries on earth, in terms of a moral imperative to work hard, save money, to do well," Inglehart said.