Application of the Limited Enthusiasm Model with Reversion, Written in 2022.

The Scottish Episcopal Church (SEC) is an Anglican Church in Scotland. Unlike its fellow Anglicans in England, the SEC is not established. In Scotland, establishment lies with the much larger Presbyterian church. As such, the SEC has less coverage of Scotland and is a much smaller church.

The Scottish Episcopal Church contains a mixture of churchmanships and has steadily declined for most of the twentieth century. This analysis investigates the likelihood of decline leading to denominational extinction.

Estimating Model Parameters

I will use the Scottish Episcopal Church’s membership and attendance data to estimate the parameters of the Limited Enthusiasm Model with Reversion. Using this cut-down version of the Demographics Model avoids estimating values for child retention among church members, hardening rates etc. There is no information about these values for this church. The reversion model has only five parameters:

  1. Reproduction Potential
  2. Duration Enthusiastic
  3. Loss Rate
  4. Fraction of Converts who Become Enthusiasts
  5. Initial Fraction of Enthusiasts in the Church

The key parameter is the reproduction potential. If this potential is less than one, then the decline of the SEC is to extinction.

Calibration Strategy

The best fit between data and model is found using least squares. Avoiding systematic deviations from the data can help reduce the number of best fits. To help find the most suitable parameter values, I vary parameters 3-5 above and optimise for 1-2, the reproduction potential and duration enthusiastic. Out of this optimisation set, I count how many indicate the church will become extinct. Although these parameter values cannot be determined with certainty, the likelihood of extinction is more robust.

Membership 2000-2019

I took the membership data from Scottish Episcopal Church publications and Brierley (2008-2020).

Virtually every optimisation indicates that the Scottish Episcopal Church will end up extinct.

A typical optimisation is given in figure 1. The reproduction potential chosen was an average figure of 0.68, well under the extinction threshold of 1. As I have done with other declining churches, I chose the fraction of converts who become enthusiasts as 10%. If I had used 50% for this parameter, the average reproduction potential would increase to 0.83. However, there is no evidence for this many converts becoming enthusiasts.

Scottish Episcopal Church and the Limited Enthusiasm model of church growth
Figure 1: Data Fit for the Scottish Episcopal Church Membership and the Limited Enthusiasm with Reversion Model

Range of Optimised Parameters 2000–2019

The optimisations for 2000–2019 indicate a large range of possible parameter values:

Reproduction Potential0.5–0.97
Duration Enthusiastic1-11 years
Loss Rate
(Reversion and Deaths)
Fraction of Converts who Become Enthusiastsabout 10%
Initial Fraction of Enthusiasts in the Church0.5%–3%
Model Parameters for the Scottish Episcopal Church

If I had used 50% of the converts enthusiast, then the upper part of the range for the reproduction potential would be just over 1. However, although this value would just avoid extinction, it is only possible with a very high loss rate masking conversions. In my experience of the church, I have seen no evidence to support this scenario.

I repeated this optimisation strategy for different values of the total population, starting with the full Scotland value, then using lower values. It is possible the SEC has a restricted influence in society and has contact with only part of the population. The model might give a more optimistic reproduction potential with a lower population. Extinction occurred in all such optimisations.

Possible Extinction Date

Although the model predicts extinction, it does not indicate an extinction date. The model contains exponential decline because it does not capture the effects of ageing. By 2045 it forecasts a church with 12,000 in attendance. This is probably too optimistic.

Fitting a straight line to the membership data gives a more realistic estimate of the extinction date, as decline through ageing is a linear process. The Scottish Episcopal Church is forecast to be extinct by 2045, figure 2. This result is a marked contrast to the 12,000 of the limited enthusiasm model. In that year, the church’s attendance will likely lie somewhere between the two figures, kept from extinction by a small number of vibrant congregations.

Figure 2: Linear fit to the Scottish Episcopal Church membership data.

Long–Term View

The membership of the Scottish Episcopal Church from 1900 to the present day shows the classic institutional lifecycle, figure 3. The church has declined since 1920, an earlier start compared with most other UK denominations. Nevertheless, its decline is slightly slower. I have no easy explanation for these differences. The slower decline may be influenced by English migration into Scotland, As English people often find the style of the SEC more familiar than the established Church of Scotland.

Figure 3: Membership of the Scottish Episcopal Church

Personal Reflection

I came to faith in a congregation of Scottish Episcopal Church. The people in this church taught me the basics of the Christian faith and what it means to know and follow Christ. So, documenting this decline is far from academic but gives me immense sadness.

I was very aware that my experience of the SEC was far from the norm. Our congregation was evangelical, moving with the Holy Spirit, with regular conversions. It has continued that path until today and has grown considerably. It is one of only 8% of SEC congregations with more than 100 people attending (using 2014 figures).

By contrast, most SEC congregations are small. In 2014, 50% of these congregations had an attendance of less than 30, and 25% had less than 16. Most of these were declining and are likely to disappear in 10 years. The denomination continues to take a liberal direction, especially in areas of human behaviour and biblical authority. It is a far cry from a church that seeks converts through the power of the Word and the Spirit. My hope and prayer is that the SEC changes direction before it is too late to survive.