Pew Research Center Notes Global Decline in Religiosity at Harvard Divinity School Talk

Pew Research Center associate director Conrad Hackett discussed the global decline in religion and its correlation with development at a Harvard Divinity School event on Monday.

The talk — facilitated by Harvard Divinity School lecturer Gina A. Zurlo — focused on the results of a global religious trends report published by the Center in June titled“How the Global Religious Landscape Changed from 2010 to 2020.” The report found that Muslims were the largest-growing religious group and noted an increase in the proportion of the religiously unaffiliated population.

“The world’s countries are generally becoming less religious,” he said.

Hackett framed this decline through what he called a “secular transition,” a long-term process that is directly correlated with the decrease in fertility and mortality rates.

The transition takes place in three stages: early, medium and late, Hackett explained. Societies first see a decline in religious participation, then a decline in the number of people who view religion as important, then finally a decline in the number of people who identify as religious.

“People are going to church, mosque, synagogue, less frequently in the medium stage of a secular transition, which is where we think the United States is right now,” Hackett said.

Hackett also said that younger generations, particularly in wealthy, industrialized countries, identify with religion at far lower rates than older adults.

To illustrate the generational shift, Hackett showed a chart from The Harvard Crimson’s Class of 2027 demographics data, noting that 46 percent of the students identified as atheist or agnostic, up from 32 percent just a decade earlier.

“In many countries you see patterns similar to Harvard undergrads — young people are growing more secular,” he said.

According to the Pew report, the religiously unaffiliated population proportion grew in 35 countries, mostly in Europe and including the United States. During the same period, the proportion of Christians declined by five percentage points in 40 countries, whereas Muslims—the world’s fastest-growing major religious group — rose by nearly two percentage points as a share of the global population.

Hackett emphasized that religious switching — from any religion to no religion, for example — has become a powerful global trend. For every one person who joined a religion, Pew found that 3.2 left the religion in which they were raised.

The researchers also discussed how varying survey methods and categorizations caused some differences between databases in results .

Zurlo, who is an editor for the World Christian Database, pointed out that the biggest differences between Pew and the WCD is that Pew reports more non-religious people in Asia while WCD reports populations that are far more religious. For instance, WCD reports China as 61 percent religious while Pew reports it as 10 percent religious.

“That is a huge difference for a country of 1.4 billion people,” she said.

“A big question on how religious the world is is how religious East Asia is,” Zurlo added. “What defines religion in East Asia, and can it be measured the same way as we measure religion in Western settings?”

Zurlo added that the WCD reports “tens of millions” of Chinese Christians who are affiliated to the unregistered churches that do not show up on surveys and government data.

She also pointed out that some differences stem from categorizations. The Pew Research Center, for instance, categorizes populations into six religions, whereas WCD uses 16 religious categories, plus separate counts for atheists and agnostics.

Pew also relies heavily on surveys, while WCD draws more extensively on institutional reports and data gathered by religious organizations, especially in areas where religious minorities face political risk.

“Official data doesn’t always tell the whole story of what’s happening on the ground,” Zurlo said.

Zurlo acknowledged that many people — especially younger generations — identify as “spiritual but not religious,” which complicates attempts to categorize them.

Despite the slight decline in religiosity, Zurlo said that the world is still a “very religious place.”

“More people are being born into religion than into non-religion right now,” Zurlo said. “So keep coming to Div School — finish your degrees.”