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Church Growth Modelling

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Model Construction

Institutional Model

Church recruits in proportion to size, but recruitment rate reduced by institutionalism which grows as church grows.

Extended Institutional Model

Used for application to GB Methodist Church.
Growing population, delays in cause and effect, internal pressures for institutionalism.

Model Results

Application to GB Methodists

Data fit to the model.

Growth & Decline of Welsh Presbyterians

The connection between revival and institutional growth and decline.

Related Blog

Institutionalism and Church Decline

Response to comments by others on the negative effects of institutionalism on church growth.

The Rise and Decline of British Methodism

Application of the Institutional Model of Church Growth.

Institutionalism Causes Church Decline

Results of the Institutional Model

As a church denomination grows, so does institutionalism. Institutionalism reduces recruitment/conversion, leading to the church decline to extinction. Institutionalism needs to be combated to prevent decline continuing and return to growth.

Institutional Lifecycle & Church Decline

Consider a small church denomination with no institutionalism and an annual recruitment rate of 8%, well in excess of its loss rate 3%. The initial church numbers are normalised to 1. It is given a very low rate of combatting institutionalism.

The church grows exponentially with a corresponding, though delayed, growth in institutionalism, figure 1. Church growth starts slowing (inflexion point) after 35 years, whereas institutionalism continues to accelerate until about 50 years. Church peaks at 65 years, around 10 times its original value, and then starts to decline. However institutionalism continues to grow until year 140. This long delay is because the church takes no action to combat institutionalism and relies on the very weak natural attempts to reduce it. Institutionalism declines too slowly to prevent church extinction.

Figure 1: Church Growth with Decline Caused by Institutionalism

In reality the decline in the church will be straighter, and extinction earlier, due to the aging process.

A comparison of the recruitment (add to church) and leaving flows, shows the rapid decline in recruitment from year 50 due to pressures to service the needs of the institution, figure 2. Recruitment declines faster than the leaving rate, thus decline and extinction are inevitable.

Figure 2: Comparison of Recruitment and Leaving Rates in the Church

This pattern of growth and decline can be seen in many pre-1900 UK and USA denominations, e.g. the UK Methodist Church, figure 3. Although the timescale is longer, and the overall population grows over the period in the UK, it exhibits a similar growth and decline pattern to the model. Although institutionalism is not easily measured, it is known that over this period the Methodist church moved from a very flexible and lay oriented church to a parochial, building-centred church with a professional ministry with a greater integration into society - traits of institutionalism.

Figure 3: Growth and Decline in a Typical UK Pre-1900 Denomination.

Combatting Institutionalism

It is most likely that a church will not combat institutionalism until numerical decline has been set in for some time. This is because the growing church will have seen increasing institutionalism as giving positive benefits, and even helping growth.

Compare three policies to combat institutionalism with the base case of no policy. The policies with increasing effect are called weak, medium, and strong. Such policies are introduced by the church denomination 20 years after decline has started as an attempt to deal with decline. Likewise the policy will cease 20 years after growth has returned. It is likely that after 20 years, half a career, there would be a number of new church leaders that were not impacted by the crises of previous decline and have less interest in reducing institutionalism.

The policy increases the parameter attempt to remove institutionalism. This is a "switching" form of feedback between the decline of the church and institutionalism.

The base run and the three policies are identical until decline has set in, figure 4. Churches often find external contextual explanations for decline before deciding it due to internal reasons. The weak policy (run 1) slows the decline but is not sufficient to give a return to growth. Eventually decline increases again.

Figure 4: The Effect on Church of Three Different Policies to Combat Institutionalism

The medium policy (run 3) has enough strength to return the church to growth, but that the policy is discontinued after growth is sustained gives a return to decline. The strong policy (run 4) gives a much faster return to growth, and a higher peak. The oscillations are caused by the repeated discontinuing of the policy. If the policy is continued even when growth returns, then the church can be stabilised at a level as high as the original peak with an even weaker policy than the ones in figure 4.

The effect of the three policies on institutionalism are shown in figure 5. Note in all three policies Institutionalism does not drop particularly low. Church decline can be reversed without having to dismantle institutionalism completely.

Figure 5: The Effect on Institutionalism of Three Different Policies to Combat Institutionalism

A very strong policy, twice as strong as the strong one in run 3 figure 4, is show in figure 6. Run 3 shows it is possible to combat institutionalism and produce higher future growth even if the policy is discontinued on growth. Although there is oscillation, the church can stay at a very high average level.

Figure 6: Policy to Combat Institutionalism That Gives Increased Growth

Strategies to Combat Institutionalism


Deal quickly with institutionalism when decline sets in. The longer the delay in dealing with institutional causes of decline, the less effective any policies will be and they may not even reverse decline, see figure 4.


Do not reduce policies to combat institutionalism when growth returns. It is important that dealing with institutional causes of decline are seen as a long-term strategy that is continued and not modified just because growth returns. Otherwise a growth and decline cycle may set in, a form of institutional boom and bust, figures 4 and 5.


Policies are needed to deregulate how congregations operate. Let a denomination divide up into smaller groupings with different beliefs, for example, liberal and conservative persuasions. Allow congregations to join the group they identify with the best, or go independent. The need to convert and save people should have a higher priority than the needs of the institution.

Allow congregations to pay for their own ministers and not have to send money into a central denominational pot. This increases ownership among the people who need to be involved in conversion. Let congregations keep all their income, so that if successful they can invest in their work, or that of their chosen associates. Let congregations choose ministers from outside denominational ranks, and adapt their operational management and clergy structures. What is left of central denominations can provide support services, pensions, advice etc, on a consultancy basis.

Such deregulated denominations would allow spiritual renewal to flourish unhindered, with healthy competition driving up standards. Enthusiasts would be generated, conversions would follow. Without enthusiasts, the Christians who make converts who become enthusiasts, the church cannot either survive or fulfil the great commission. See the Limited Enthusiasm Model.

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Church Growth Modelling