The original model was developed by James F. Engel and Viggo Søgaard. It was later refined by Engel, who added several ideas from behavioural science, and published it in his 1975 book with W.F. Norton What's Gone Wrong With the Harvest and 1979 publication Contemporary Christian Communications.3
The model emphasises the journey of faith and spiritual maturity through a number of stages.4
Two possible additional stages before stage eight could be: -9 Unawareness of supreme being. -10 Resistance or antagonism to the concept of a supreme being.
The Engel scale has been criticized for its fixed linear approach, which has led to a number of modifications.5 Søgaard developed the Engel Scale into a two dimensional model in 1986.6 The Gray Matrix, another two dimensional model produced by Frank Gray of Feba Radio, and Thom S. Rainer's Faith Scale are both also derived from it.7
Søgaard, 2000, p.311 ↩
Love, 2000, p.231 ↩
Hartman, 2007, p.74–75 ↩
Hazelden, 2000 ↩
Hartman, 2007, p.75–76 ↩