Can someone explain the difference between the 'Simple' and 'CAGR' methods?

Can someone please break down the difference between the two? What exactly do they calculate and not calculate?

I have a 14% per annum return difference when I switch between them in my Australian portfolio.

Essential it is this:

A simple annualised return simply divides the rate or return for the period by the number of years in the investment period.

A compound annual growth rate calculates the year on year growth rate that would be required to achieve the same result.