The Church R-Number

During the Coronavirus pandemic there has been a lot of discussion of the “R” number, the Reproduction Number.

The Government helpfully explain that if R is 2, on average, each infected person infects 2 more people. If R is 0.5 then on average for each 2 infected people, there will be only 1 new infection. If R is greater than 1 the epidemic is growing, if R is less than 1 the epidemic is shrinking[1].

Sociologists have often used the “touch” concept to look at church growth[2], because one of the key ways in which the church grows is by contact between those who believe and those who do not. If the church has an R number greater than 1 it will grow; if it has a number less than 1 it will shrink.

One of the big questions of history is how a tiny Jewish cult from Jerusalem took over the Roman Empire in less than 300 years. This was a remarkable achievement, but the compound effect of growth  means that the rate of increase involved was not so much explosive, as it was relentless. Sociologist Rodney Stark posits an R number of 1.4 a decade[3]. That would mean that a church of 10 would become a church of 14 over 10 years, which is certainly achievable. When this is done over and over again, you change the world.

The Early Church didn’t change the Empire overnight (explosive growth), but it did manage to keep its evangelistic outlook until it started running out of Romans to convert (relentless growth).

This unfortunately contrasts with the church of today in Britain, where the R number would appear to be well below 1.

I have used as an example the Methodist Church of Great Britain (because I have detailed figures), but other Mainstream Protestant denominations have very similar issues.[4]

The decadal R number has been less than 1 every year since 1934 – the year after Methodist Union –before that it had been growing again after the losses of the First World War.[5]

Remember that this chart represents not the size of the church, but the speed of its decline. The decadal R number may not be going down any further since it has reached about 0.68, but that is still the fastest rate that the Methodist Church has been declining – ever.

On a Micro level, that is a church of 10 becoming a church of 7 over a decade, which is sort of the opposite of the Early Church’s 10 becoming 14. It may not be instant collapse, but when it happens relentlessly, there is only one destination.

If it doesn’t get back above the red line, the church will disappear – the lower the chart goes, the faster that decline will be.

So what can we do?

Well I have written extensively on this in the past, but the short answer is “Absolutely Anything Different”. We might fear throwing the baby out with the bathwater, but the statistics show that the baby grew up and left years ago.

The “From Anecdote to Evidence” report of the Church of England from 2014 had this to say: “it is not so much the particular style of worship which is important, but rather the fact that it was chosen rather than inherited.”[6]

I would interpret this loosely as: if you have an R number of 0.68 in your congregation, then try absolutely anything else you can – you have nothing to lose.

Now I know there will be those clergy reading this Blog who will be thinking that it is easier said than done to make changes in midstream when there is so much inertia against you. I know. I have been there.

What could help, however, is if there was some uncontrollable outside event which shut down churches for say, a whole 6 months. In that unlikely event, might there be the opportunity to start again with something completely different?

There is no point in going back to the 0.68 so why not start again?


[1] https://www.gov.uk/guidance/the-r-number-in-the-uk#what-is-r

[2] https://www.tandfonline.com/doi/abs/10.1080/0022250X.1999.9990223

[3] http://humanscience.org/docs/Stark%20(1996)%20Rise%20of%20Christianity%201-2.pdf

[4] I estimate the URC has an R number of 0.65, and the Baptist Union 0.83. Anglicanism is more problematic as there is a different concept of membership, but the Average Weekly Attendance (October Count) gives an R number of 0.86

[5] The real R figures are worse than these – for simplicity I have made no attempt to include population growth in my analysis – as a proportion of the population, Church Membership has declined even faster.

[6] https://www.churchofengland.org/sites/default/files/2019-06/from_anecdote_to_evidence_-_the_report.pdf page 30