LONDON (RNS) — The reputation of the world’s oldest Bible Society and one of the leading international polling organizations has been tarnished in the fallout from a survey that was said to rewrite understanding of Christianity in Britain — and has now been junked for being fraudulent.

Last year, amid huge headlines about a turnaround in Christian fortunes in Britain, the Bible Society unveiled its survey “The Quiet Revival,” which it said showed that the numbers of young people who were attending church had skyrocketed. Specifically, the report found a 12 percentage point spike in monthly churchgoing among 18- to 24-year-olds, from 4% in a 2018 survey to 16% by 2024.

At the time, the Bible Society announced in “The Quiet Revival” that this survey showed a reality that could not be denied. But this declaration turned out to be false.

Leading pollsters and some journalists had questioned the survey’s results, given they were so at odds with other studies of churchgoing and religious belief, but they were constantly rebuffed by the Bible Society, which stood by its report.

And now, almost exactly a year since it was issued, the society has announced that its polling company, YouGov, has acknowledged the data used in the report was flawed. Anti-fraud devices to ensure that the sampling is accurate were erroneously not switched on by YouGov.

It is a major blow for the Bible Society, first founded in 1804 and the origin for the worldwide Bible Society movement. Interest in the revival study not only raised its profile but led to considerable discussion in Britain about religious adherence, with talk of a turnaround in Christian affiliation after years of reported decline.

But it is also a significant moment for YouGov and, more widely, the polling industry. The days of carrying out in-person, one-on-one interviews are long gone. Instead, some pollsters use online opt-in methods for polling. YouGov offers rewards or points for completing surveys, with the risk that this might lead people to provide answers that are not accurate.

YouGov CEO Stephan Shakespeare apologized for the errors. “YouGov takes full responsibility for the outputs of the original 2024 research,” he said. “We would like to stress that Bible Society has at all times accurately and responsibly reported the data we supplied to them.”

Paul Williams, the Bible Society’s CEO, told an online briefing held by the Religion Media Centre that the society had gone back to YouGov on several occasions and asked about the quality of the data. The society, he acknowledged, had come under “intense scrutiny” about the report, and he said YouGov had brought in a data security team that uncovered the errors.

“They told us they’d failed to activate these key quality control technologies, so the whole sample was damaged. This is YouGov’s mistake, not ours,” Williams said.

RELATED: Cancer nurse turned archbishop celebrates election as first woman to lead Church of England

But David Voas, emeritus professor of social science at University College London and a specialist in research on religion, was critical of the Bible Society’s approach to the survey. He said the society was also responsible, and the findings were “too good to be true.”

“The Bible Society brought these problems on themselves,” he said at the online RMC briefing. “Experts have been telling them for the better part of a year, not only the figures are wrong, but why they’re likely to be wrong — bogus respondents and other problems that infect opt-in online polls — and they just refused to sit down with other academics and talk about that.”

Voas said it has become standard practice in social science to make underlying data available to other researchers, but the Bible Society had declined for a year to let others study the material.

Another leading polling expert, Sir John Curtice of the University of Strathclyde, warned that accuracy in research is becoming more difficult due to the advent of bots and artificial intelligence, which can affect the results of opt-in surveys.

According to Chris Curtis, a market research expert who has worked for polling companies including YouGov and the British government, fake accounts or bots are a major problem for the polling industry.

“In practice they are often just large numbers of fake or semi-automated accounts, controlled by one person, all trying to extract those payments at scale,” he wrote in his Substack post, “Young Men, Bad Data and Moral Panic.”

Unlike Williams, Curtis did not blame YouGov, and he warned that the polling industry has become a major problem.

“It has said that the issue here was caused by human error, where key quality control technologies were not activated. Many other companies would not even have bothered with such technologies in the first place.”

Meanwhile, the Bible Society is maintaining that although the report may have been flawed, its general thesis — that there is a resurgence in Christianity in Britain — still stands, and that there is a new openness to religion and spirituality, which other Bible Societies around the globe have also noticed, and other, smaller Bible Society surveys in Britain have reported.

Williams noted that Bible sales have risen in Britain by 106% in six years and registrations for the Alpha course on Christianity — popular in both Anglican and evangelical churches — have increased by 35% in one year.

Although religious identity overall is shifting from Christian to “no religion,” the Bible Society says younger adults are getting involved and are more committed and active.

“There are good reasons to believe that the fundamental direction of change, evidence in the main findings, points to something real in the world,” said Williams. “It should make us curious, therefore, about the extent of that, the reasons for that.”

The Bible Society says that it will run the YouGov survey again this year and, meanwhile, it will continue to conduct other research into attitudes toward the Bible, faith and spirituality. It has produced another report about changes to spirituality in Britain, using a variety of existing data. The charity, which has a sizable income of 26 million pounds a year, once focused on publishing Bibles, which it still does, but now combines that work with commissioning research.

Among the issues that advocates of a Christian resurgence regularly raise is the rate of adult conversion to Christianity. The Church of England reported that teenage and adult baptisms rose by nearly 1,000 — from 7,800 in 2024 to 8,700 in 2025. On Easter Sunday (April 5), thousands of people are going to be received into the Roman Catholic Church in England and Wales. The two Roman Catholic dioceses that cover London are showing marked increases in numbers of new Catholics. In the Diocese of Westminster, for example, 800 adults are due to be received into the Catholic Church, the highest number for 15 years, while in Southwark there will be nearly 600 – the highest number for 26 years, bar one other year.

But baptisms of infants are falling in both denominations, Voas said, because their parents are leaving behind church attendance.

“The dominant trend,” he said, “continues to be quiet quitting, not quiet revival.”

RELATED: The Gen Z revival being debated won’t happen in churches that talk but don’t listen