Stella 9.1 model can be downloaded from http://forio.com/simulate/jhayward/lbdr-new-church-1990-2000/model/download/?hard=true.
Model author: John Hayward, Church Growth Modelling.
Demographics Model Simulation
"New" Churches 1990-2000
The central hypothesis of the limited enthusiasm model is that conversion growth in the church is driven by a sub-group of church members called enthusiasts. The demographics model adds births, deaths, reversion and secularisation.
This model is the simulation in "A General Model of Church Growth and Decline", Journal of Mathematical Sociology, Hayward, 2005. It was achieved by optimising four parameters next to membership data from Christian Research, 1990, 1991, ... 2000. The four parameters are the reproduction potential, the duration enthusiastic, the reversion rates (set equal) and the initial fraction of the church enthusiast. The optimised parameter values appear in the first line of table 1 in the paper.
The survey data for the New Churches could not be used as the 1979 point was unreliable, leaving it with only two points. This was not enough to estimate the curvature which is essential to parameter estimation. Survey and membership data for 2000 onwards indicated the overall New Church growth did not last overall, but that the growth has been maintained for the New Frontiers new church stream.
Opens in separate window: http://forio.com/simulate/jhayward/lbdr-new-church-1990-2000.