Pursuing a Mathematical Model for Mentoring and Business Coaching

I wold like to develop a model for mentoring or business coaching and how it affects the profit growth curve of the mentee or person being coached. It would be nice to draw two hypothetical profit growth curves, one of them without mentoring or business coaching and the other with mentoring or business coaching included. A third curve can be drawn representing profits of a client after deducting the mentor or coach share. This third curve should be higher, at least on the long term, from that without mentoring or business coaching. The area under the third curve should be greater than that under the first one at least within the first 3 to 5 years.

The question would be how to calculate such numbers, which formula to use and how to come up with a formula for profit growth in the first place? One possible answer is to base this on stats. Mentor or business coach may start collecting stats for those being mentored or coached. Such stats can serve as a way to construct the profit growth curves. It still would not be possible to compare such curves with those of the same person had he or she not been mentored or coached yet it is still possible at least to compare the aggregate of such profit growth curves with those curves of others who have not been mentored or coached. This could provide a clear indicator of the benefits of mentoring or business coaching and, to an extent, quantify the value of mentoring and business coaching.