As a church denomination grows, it needs to develop structures to support the denomination: full-time ministers, training, buildings, governing bodies etc. However, the larger the church becomes, the greater effort is needed on maintaining the institutional structures; thus, less effort is available for conversion and recruitment.

The model predicts that growth comes to a halt and that without interventions to dismantle some denominational institutionalism, the church denomination eventually dies due to institutionalised lethargy.

This is a sociological model whose purpose is to understand church growth and decline using principles from the sociology of organisations and religion.


As a church denomination grows, resources are needed to support its organisational structure. Such resources, once set up, need to be maintained. They may acquire their own reasons to exist and lose their connection with the church’s recruitment and conversion mission. It follows that the resources tend to be easy to construct but hard to dismantle. Thus, they continue to be maintained long after their usefulness to mission has waned. They cannot be easily scaled back just because the numbers in church decline.

The greater these institutional resources, the more institutionalised the church. This will be represented by a single soft variable “Institutionalism”.

Examples of institutional resources include:

  • Physical buildings. Growing congregations move from rented buildings to purpose-built ones. Once built, they cannot be easily reduced in size if the congregation declines, which leaves fewer people to maintain the same sized building.
  • Paid ministers. As churches grow, they can afford to turn lay ministers into paid ones. When the church declines, it is not so easy to shed paid staff who now rely on the church for their livelihood.
  • Ministerial training. As churches grow and mature, they can afford the time and money to invest in training and education of ministers. This creates a more specialist role for ministers and a higher entry bar for novices. Thus, a declining and smaller church may not find sufficient people to fulfil the ministry positions whose entry standards remain intact.
  • Church programmes. Growing churches increase their number of programmes, internal and external, to assist growth and help the community. Once the church declines, the programmes demand more individual effort to maintain due to less available people; thus, less effort is available for evangelism.
  • Centralised leadership and support staff. As denominations grow, they require central staff, bishops, moderator, support staff to function. Such staff are not easily shed in a declining church, which cannot quickly reduce the number of dioceses, presbyteries etc.
  • Governing bodies. Growing denominations add local and national governing bodies to function. The number of such bodies does not decline as fast as the church. Therefore, too much time is spent in now redundant or inappropriate administrative structures.
  • Territorial boundaries. Growing denominations allow congregations to develop parish boundaries over which they have control. When the denomination declines, still successful congregations are prevented from expanding into areas controlled by dying congregations.
  • Internal politics. As denominations grow, people inevitably generate sub-networks to maintain a group of people they can get to know. Such networks encourage like-minded people to bond together, thus creating different factions. Such groupings become unsustainable as the denomination declines, but the political emphases of the groups may still control the denomination and prevent newer renewal groups.
  • Pastoral needs of church members. As churches grow, people can rely more on the pastoral help of professional ministers, rather than lay support. As churches decline, people are reluctant to fall back on the care of laypeople, many of whom no longer have the skills to support others. People prefer to see a “proper” minister rather than a layperson.
  • Expectations of church members. As churches grow, they have most of their religious services in the hands of professional ministers. The people’s expectation is that a church is not a church unless it has such a minister, often fully trained and full-time. That expectation persists in declining churches giving a lack of confidence in lay-run churches.
  • Expectations of society. As churches grow and become part of the fabric of wider society, that society has high expectations of what church can deliver, and the professional standing of its leaders, expectations that cannot be met by declining and now smaller churches.


The model consists of one group of people: Church, measured by attendance or membership of the denomination. There is one other variable: Institutionalism, representing all the organisational structures put in place as the denomination grows. Institutionalism undermines the ability of the church to add people to its ranks as more time is needed to maintain the organisational structures.

The dynamic hypotheses are:

Dynamic HypothesesDescription
Church recruits in proportion to its size (R1).The larger the church, the more people are available to seek and disciple new converts, and resource structures that assist growth. Thus more are added and more growth results.
People leave church at a constant proportional rate (B1).This includes people giving up the church and deaths. The reasons people leave are personal; thus, the rate is proportional to the church size, i.e. “per capita”. Those who leave may rejoin as the source of recruits is potentially infinite.
As churches grow they become more institutionalised, thus reducing the effectiveness of their recruitment (B2).The more people in the church, the more it becomes institutionalised. Thus fewer people are added to the church.
The nearer the church gets to institutional capacity, the harder it becomes to become more institutionalised (B3).Institutionalism can quickly increase when churches are small, but as churches become large networks of congregations institutionalism saturates to a maximum. The very nature of an institutionalised organisation is to resist change. Thus there is a fixed capacity to possible institutionalisation.
There is internal pressure to reduce institutionalism (B4).There are people within the church who attempt to reduce institutionalism, perhaps because they see its dangers, or because they are rebels. This is done in proportion to the degree of institutionalism, i.e. the more institutionalism, the more effort there will be to reduce it.
The desire of institutionalised people to increase institutionalism (R2).There is a counterforce to B4 from people in the church who wish to increase institutionalism, perhaps because they see its benefits to them, their churches, or perceive the institutional forms to be good. This is done in proportion to the degree of institutionalism, i.e. the more institutionalism is the more effort there will be to increase/maintain it, given the slowing effects of B3.
Unlimited pool of unbelievers.The size of society outside the church is infinite.

Births are ignored but children born to church members can be assumed recruited the same way as those outside the church.

System Dynamics Model

Unbelievers are added to the church according to the size of the church (R1) but reduced according to institutionalism (B2), figure 1. Church members leave at a constant rate per person (B1). Institutionalism is generated according to the size of the church (B2). Institutionalism is easier to generate as it grows (R2) but becomes harder to produce as it approaches capacity (B3). Attempts to reduce institutionalism occur at a constant per capita rate (B4).

Figure 1

The leaving feedback loop B1 has a constant impact. However, because loop B2 reduces the recruitment effectiveness of the church members, the reinforcing loop R1 has a diminishing impact on recruitment. The limit to church growth is reached when the recruitment rate matches the leaving rate, after which the church declines.

Scope of Applicability

The Institutional Model is applied to a whole denomination, or a collection of national denominations, and is less applicable to an individual congregation. It is similar in form to the Self-Enhancing Resource Model that models limits to congregational growth.

Model Parameters

The behaviour of the model is controlled by parameters that reflect the church’s effectiveness:

church recruitment rateThe potential rate of recruitment given institutionalism is negligible.
church leaving rateThe fraction of church members who leave each year.
growth rate in institutionalism due to church sizeThe effect church has on the rate of increase in institutionalism if there are no internal pressures to either increase or decrease it, and it is far from capacity. (Not in diagram)
pressure to keep institutionThe internal effect church members have on increasing institutionalism if there are no internal pressures to decrease it, no effect of church size to increase it, and it is far from capacity. (Not in diagram)
attempt to remove institutionalismThe fractional rate at which institutionalism can be removed, given there are no pressures to increase it.
max institutionalismThe capacity or upper limit to institutionalism. With a scale transformation, this can be set to 1 without affecting the behaviour of the model. This fixes institutionalism units as a fraction of its capacity. (Not in diagram)

Results of the Institutional Model

Church starts by growing (R1), with the institutionalism also growing (B2 and R2). However, church growth slows as the impact of B2 reduces that of R1. Church growth slows as the impact of R1 falls below the impacts of B1 and B2. Eventually, recruitment falls below the leaving rate and church declines. Without intervention, then institutionalism declines too slowly to prevent the church from becoming extinct.

See Institutional Model Results.