The election of Pope Leo XIV, the former Cardinal Robert Prevost, has been met with welcome by some who have praised him as “a calm and grounded leader”, with a former colleague saying: “No matter how many problems he has, he maintains good humour and joy.”
Others are less enthusiastic, some using blunt insults I’m not keen to share here, even if it is regarding a leader of a faith I don’t personally follow (my own opinion? Anyone who plays Wordle religiously can’t be all bad…)
One thing that every news outlet could agree on: the number of Catholics that Pope Leo XIV would be leading:
As the leader of close to 1.4 billion followers, a population that equals the size of China or India, Pope Leo’s words matter to nearly one out of every six people in the world.
Whether it is the New York Times as above, the South China Morning Post or France 24, everyone seems to agree on how many Catholics there are in the world.
But where exactly does this number come from? According to the Catholic News Agency earlier this year, these figures come from the 2025 Annuario Pontificio and the 2023 Annuarium Statisticum Ecclesiae reports, which are published in Italian, aren’t available as a PDF or from a library, and must be purchased for €74 and €48 respectively. I must confess that while I’m curious about how these figures were reached, I’m not a-hundred-quid-and-learn-Italian levels of curious.
With my apologies for relying therefore on the Catholic News Agency and Vatican News coverage of the numbers, it seems that the Central Office for Church Statistics collects numbers of Catholics reported by dioceses and adds them all up.
How do the dioceses know how many Catholics there are in their patch? The simple answer would seem to be that they count the number baptised – after all, the Code of Canon Law considers that a person is Catholic if they’ve been baptised and haven’t officially repudiated the faith. There are a few complications, of course: most obviously, keeping track of the baptised people who all eventually die, but also – and probably of less concern to the church – that some baptised people stop being practising, believing Catholics.
Diocesan statisticians take various approaches to this conundrum, including a method suggested by American researcher Michael Cieslak of the Catholic Research Forum, which takes account of secular records of births and deaths, Catholic records of baptisms and Catholic funerals. Cieslak then uses these figures to come up with a reasonable estimate as to the proportion of the population who are baptised Catholics at birth, remain Catholics at death, and smooths the number over the population to come up with a reasonable estimate.
To his credit, Cieslak doesn’t shy away from some of the issues with this approach:
The single greatest weakness lays in the fact that measurements only are taken at two points of a person’s life: birth and death.
While he focuses on people moving house and migrating in the intervening years, something else important can happen in that time that he indirectly acknowledges:
The Code implies that a person is considered a Catholic if he/she is baptized a Catholic and does not formally repudiate his/her faith.
Plenty of other people do of course stop being a Catholic during their lives without formal repudiation, but this method would only find out about their leaving the religion when they die, potentially many decades after the fact – and even then, only if they do not receive a religious funeral, which anecdotally many atheists still receive in order to placate still-believing family members.
If you were baptised and are wondering if the Roman Catholic Church is still counting you, it seems highly likely that it is. Carefully and demographically smoothed statistics won’t register if – for example – significant events cause a sudden precipitous drop in adherents, as has happened with the various church child abuse scandals around the world.
Cieslak also adds that it is not clear that all – presumably US – dioceses use as rigorous a method as this, and while he was writing in 2012, it seems highly likely that the same issues exist today:
The burden lies with the local researcher to catch these anomalies and adjust the final counts.
It is also unclear that territories outside the USA are as rigorous as Mr Cieslak.
In England and Wales, the Benedict XVI Centre for Religion and Society at St Mary’s University reports that 6.2 million people in the UK say they were brought up Catholic in their 2018 report Contemporary Catholicism in England and Wales: A statistical report based on recent British Social Attitudes survey data, but that only 3.8 million consider themselves Catholic. While I was unable to establish how England and Wales’ dioceses report to the Central Office for Church Statistics, it is notable that the Bishops Conference of England and Wales uses the higher of these two figures, the 6.2 million who were brought up Catholic – essentially those who are baptised.
This rather suggests that those responsible for reporting such numbers aren’t overly worried about overreporting by including lapsed Catholics when discussing numbers.
The same issue exists in many other countries, in some cases far more clearly. For example, we know quite precisely how many people no longer consider themselves Catholic in Germany each year, as the nation registers believers in the tax system, and so when 400,000 people left in 2023 and more than half a million left in 2022, this was recorded by the government. In the last ten years, the Catholic population of Germany has dropped by 4 million, from nearly 24 million in 2014 to less than 20 million in 2024.
It is the same across Europe, even in a country we might assume was staunchly Roman Catholic: while Catholic News Agency coverage cites Spain as being more than 90% Catholic, the Spanish Centre for Sociological Research asked people and found that only 55% consider themselves to be Catholic, of which only a third are practising.
Even beyond increasingly-secular Europe, it seems clear the church is overcounting – by more than 40 million people in Brazil. There, government census records 64% of its 212 million population as Catholic – around 135 million – which is a large discrepancy against the 182 million the Vatican counts. Not overcounting by its own measures, of course, as it seems likely the Church remains happy with the Canon Law approach to counting: once baptised, you’re in for life.
Based only on the ten countries (Congo, Brazil, Argentina, Paraguay, Colombia, Philippines, Italy, Spain, Poland, India) that the Vatican’s press coverage listed in enough detail to compare with people’s actual response, only in India was there no discrepancy between the church’s figures and the likely real figure. The other nine were all overstated, by a cumulative total of 126 million people. Adding in reported large drops in other big-population Catholic countries, like the USA and Mexico, the discrepancy seems likely to be much larger than this.
The giddy news reports of the last month, excited about the new leader of 1.4 billion faithful, have been bizarrely happy to buy into this number. It is as if Tesco insisted that everyone who ever had a Clubcard is still a loyal customer who does their full grocery shop there every week. If a corporation made such a claim, then they’d be hauled over the coals by their shareholders and mocked in the press. It is a pity that journalists are so willing to take the Vatican’s count – which I acknowledge it believes to be true by its own rules – rather than the clear sentiments expressed by many millions of ex-Catholics worldwide.
