How People Become Christians

Anyone who has thought deeply about evangelism knows that decisions are important. In come circles, the decision to "accept Christ" becomes the end-all of the evangelistic enterprize. Years ago James Engel came up with the Engel Scale, a way of depicting the multiple decisions - or stages - of a person's response to the Gospel. Then a few years ago Frank Gray observed that while the Engel Scale mostly dealt with knowledge, it neglected the attitudinal component. This led to his development of the Gray Matrix. The Engel Scale is 1 dimensional, the Gray Matrix two dimensional. An even greater improvement would be to make it three dimensional to show the social component, one's connection with the church.

Here's a good overview of Engel & Gray.