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Membership Model
Extension of General Limited Enthusiasm Model (Births, Deaths, Reversion)
| Membership Model |
| Assumptions |
| System Dynamics Model |
| Details of Models |
| Limited Enthusiasm |
| Births, Deaths & Reversion |
| Membership |
| Renewal |
| Discipleship |
| Membership |
| Details of Results |
| Summary of Results |
| Short Term Revival |
| Long Term Growth |
| Long Term Decline |
| Growth via Renewal |
| Discipleship |
| Membership |
| References & Bibliography |
| Mathematics of Church Growth |
| Church Growth |
| Revival |
| System Dynamics |
| Sociology of Religion |
| Epidemics |
| Social Diffusion |
| Publications |
| Articles |
| Models for Download |
| Contemporary Revival-Like Movements |
| Church Growth Model Building Series |
Basic Assumptions of the Membership Model
The model is built on top of the limited enthusiasm model with births, deaths and reversion. Thus growth is driven by enthusiasts making converts and enthusiasts from those converts. In addition the children of believers may join the church at a later stage, some as enthusiasts.
The reason for the model is that most churches maintain some form of membership with varying degrees of criteria which reflects who "belong" to the church and who do not. Generally this is not the same as the attendance at the church. There are people who attend who chose not to belong. Likewise there are people who belong to the church who no longer attend.
The additional assumptions of the model are:
- Converts who start attending the church do not become members immediately. There is a delay before they join, perhaps because there are membership classes, or they need time to think of the implications of membership, or the church is slow to update lists.
- Those who are born to believers, who then go on to join the church when older, become members after they are counted as attendees. The extent of this delay depends on what age the church starts counting people as attendees, the age they allow people to become members, and the fact that many young people temporarily drop out of church before they return and then make a commitment. The model does not handle churches who count young people as members even when it does not count them as old enough for attendance.
- People who stop attending the church are not immediately taken off membership. This reflects the reluctance of churches to remove people who have left, hoping that they will return. It also reflects the fact that churches may not update their membership lists quickly
- Likewise when people die they may not be immediately removed from membership. many churches only update lists annually.
Rather than alter the structure of the main chain from unbelievers through enthusiasts to inactive believers, membership is modelled as a separate system with co-flows. There are two inflows, one for converts and one for those born into church. Both have delays. The one for those born into the church uses third order smoothing because the delays can be long and thus a pipeline delay can unduly affect numbers at early time steps. There are two outflows representing deaths and those who leave church. Again both are delayed.
The addition to the model is in figure 1:
Figure 1: Membership Model
Because of these delays membership will always lag that of attendance. This is an inevitable result of the assumptions and the SD structure. The model investigates the extent of the delay, and the difference between attendance and membership at any time.