The MTS movement has used three Cs for a long time, as a structure for ministry training: Conviction, Character and Competence.
In this post, Sandy describes a suggestion for an additional two: Commitment and Capacity:
This is one of the shortest of all the chapters (it was less than two pages), and the hard work is left to the application guide here, which speaks of the need for the 4Cs (which is familiar to those involved with MTS): conviction, character, commitment and competency.
I was particularly helped by the observation by application guide author Ken Noakes that a fifth C was needed: capacity. He distinguishes between competency to carry out a role and capacity to do so (e.g. from possessing self-discipline, time availability and management, etc.)