Counting Catholics and other religious followers

The Vatican states that the Catholic church has over 1.2 billion followers worldwide – but how do we measure the number of followers of religions?

This week’s BBC Radio 4’s More or Less: Behind the Stats investigates the counting of religion with David Voas, Professor of Population Studies at ISER.

Professor Voas explains:

“The Catholic Church tends to be a little more on the relaxed end of the scale and along with that you have got to remember it’s an absolutely huge organisation. There are more than a quarter of a million Catholic parishes.”

“In practice, parish priests are asked to estimate the size of their flock. That’s partly a function of how many people turn up to mass, but they also make some sort of guesstimate of the number who might come along for rites of passage like baptism, first communion, weddings, funerals and so on.”

“It would be one thing to count baptisms but another to count when people have left, either spiritually or physically,” says Voas.

“The Mormon Church tackles this problem in an interesting way. They basically assume that everyone stays on the books unless they hear otherwise or they turn 110. Up to that point, in principle, you could be part of statistics.

“The Catholic system doesn’t try to track people in such detail but there is a problem with counting in and not having such a good system for counting out.”

Professor Voas is currently leading a major study for the Church of England – The Church Growth programme. This is an 18 month project funded by the Church of England, which aims to provide a comprehensive study of the causes of church growth and decline.

ISER is one of three organisations commissioned by the Church of England to undertake the research. ISER’s work will involve comparing thousands of churches across the country in an effort to identify where, why and how some congregations are especially successful. The results will help the Church of England to shape its plans for the future.

Additional work on related topics is being done by groups based at the University of Durham and Ripon College Cuddesdon.


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