Religious Census 2011 – What happened to the Christians?

When it comes to religion, the sharp fall in the ‘Christian’ population has been the big story of the 2011 census.  If the 2001 results posed one problem for religious statisticians – why was the Christian figure so high? – the latest findings are just as puzzling: why has it fallen so fast?

The surge of 2001

Ten years ago, the surprise was that far more people identified themselves as Christian on the census (nearly 72%) than in various national surveys (54% in the British Social Attitudes survey).  In an article published in the Journal of Contemporary Religion, Steve Bruce and I argued that the difference in England and Wales arose because

• census forms are often completed by one individual on behalf of the entire household (although we offered evidence that this factor was less influential than had been thought);
• the census religion question immediately followed the one on ethnicity and seemed to be simply a supplementary question on the same topic;
• the wording of the question (“What is your religion?”) implies that a religious identity is expected;
• the form offered a single, undifferentiated ‘Christian’ category, and would frequently have been viewed as part of a system of cultural classification;
• and finally, anxiety about immigration and political Islam led many respondents to assert their identification with the country’s Christian heritage.

The fall in 2011

This time the issue is different.  Analysis of the full set of British Social Attitudes datasets since the survey began in 1983 shows that religious affiliation is remarkably stable, on average, over the adult life course.  Many individuals gain or lose a religious identity  (or being little concerned about such matters, vacillate in what they report), but very little aggregate change is found within any given generation.  The overall decline in religious identification is not the product of individuals defecting to no religion, but rather of elderly Christians being replaced in the population by young people who are – and remain – less religious.

That being so, it was natural to expect a similar stability in the census returns.  Of course the Christian percentage was bound to drop somewhat both because of cohort replacement and as a result of growth in the Muslim and other minority populations, but there was little reason to think that people who called themselves ‘Christian’ in 2001 would not do so again in 2011.  

In the event, the outcome has been very different. The total population of England and Wales has gone up by four million, but the number of self-described Christians has gone down by the same amount.  The Christian percentage has fallen, according to the census, from 71.7% to 59.3% between 2001 and 2011.  A decline of that magnitude can only occur if some people have decided that they don’t have a religion after all.

How many such people are there?  We’ll have a much better idea when the cross-tabulations by age, ethnicity and so on are available in the spring.  In due course it will even be possible to estimate the figure directly (and very accurately) using the Longitudinal Survey, which links records from successive censuses for a sample of the population.  In the meantime, here is a conservative estimate based on the statistics currently available.

The relative decline in Christian affiliation is the product of three factors: replacement, dilution and defection.  Old people who in overwhelming majority have a religious identity are replaced in the population by a new generation that does not.  Even if there were no absolute losses, the Christian proportion would decline as the number of Muslims, Hindus, Sikhs, Buddhists and others rises.  Once we account for these two factors, we can estimate the amount of drift into no religion.

Cohort replacement

We know from vital statistics that some 5,122,500 deaths were recorded in England and Wales between the two census dates.  We could use life tables to distribute those deaths by age, but for present purposes we can be content with a more straightforward procedure: we will simply assume that the oldest people are those who died.  Excluding about 97,200 non-Christians, 87% of the most elderly group called themselves Christian.  Based on the trajectory of generational decline in the figures from 2001, only 56% of their replacements in the population will be Christian, even omitting people of other faiths.  In a stationary population, we could thereby project that the absolute number of Christians would fall by one and a half million, and their share would drop from 72% to 69%. 

Dilution from growth in other religions

As we know, however, the population is growing, and 42% of that growth has been in the non-Christian population.  Once the additional Muslims, Hindus and so on are considered, there are still 2,320,000 more people in the country at the end than at the beginning of the period.  The challenge is to decide what assumptions to make about their religious identities.  A large proportion will be Africans and Eastern Europeans, large majorities of whom choose the Christian option.  For the moment I propose simply to apply the 2001 value (with people of other faiths omitted, 76% were Christian) to the 2011 population boost.  The net effect of growth is to dilute the Christian share to 67%.  At the same time, however, the projected number of Christians is in excess of 37.5 million, slightly higher than in 2001.

Defection

As shown above, much of the change in the Christian share of the population is the result of natural causes: the death of elderly Christians and their replacement by young people who have no religion, and a continuing growth of non-Christian groups through immigration and natural increase.  Using very generous assumptions about the amount of change produced by cohort replacement, and relatively conservative assumptions about growth through immigration, we have managed to explain about 40% of the fall in the Christian percentage of the population.  Nevertheless the calculations would not have led us to expect a drop in the Christian headcount between 2001 and 2011. 

I estimate that about 4,300,000 people in England and Wales were identified as Christian in 2001 and as having no religion in 2011.  (To be more accurate, this value gives the net change: it is very likely that many people called themselves Christian in 2011 having not done so in 2001, and hence the actual number going the other way would be correspondingly larger.)  This figure is 13% of the total number of 2001 Christians who were still alive in 2011. 

The analysis underlines the remarkable amount of change that has occurred in the relatively short period between the last two censuses.  Nearly a quarter of the people who called themselves Christian in 2001 no longer appear in that column, casualties of old age or disaffiliation.  Many of them have been replaced via natural increase and immigration, but the situation is intriguingly fluid.

What happened to the Christians?

The 72% figure was never a good indication of the religious state of the nation, and likewise the 12.5 percentage point fall between 2001 and 2011 is unlikely to be evidence of a previously unnoticed shift towards secularity.  The census findings are somewhat better aligned than before with national survey data, though for the reasons mentioned at the outset the Christian share is still on the high side.  Why the proportion has dropped by so much, though, is a question that is likely to occupy us for some time to come.

David Voas is Professor of Population Studies at the Institute for Social and Economic Research, University of Essex, and co-Director of British Religion in Numbers.