I am often asked as an Agile Coach when I know that I have been effective at my job. The answer is simple- my work as a coach is done when the team in question is capable of being predictable.
And what, you may ask is predictable? For me it is a team that is capable of consistently delivering 90% or greater of points that have been planned for an iteration. I have given this capability a name. I call it the Gold Standard.
When a team is predictable I can layout the backlog over extended time and give the business a reliable gauge of what is possible– which is a true business value that most scrum teams (and waterfall teams) are not capable of providing. Because I can more effectively short AND long term plan I can achieve sustainable pace.
There are a great number of other benefits to achieving the Gold Standard, but as long as I and the team focus on this, everything else we do are merely tactics to achieve this – usually difficult tactics that need the guidance of a good Agile coach, but tactics nonetheless.