I'm going through an intensive coaching experience. The idea is that I spend a full ten weeks with a single team.
I'm a little surprised with the outcome. I knew there would be an impact but the team is progressing a lot faster than I, for one, anticipated.
I don't have enough data to attribute that to the intensive experience, yet. It's also a really engaged and interested team and I suspect that has a lot to do with the progress being made.
I think people have a tendency to be a little superstitious in assigning reasons for success or failure. I don't want to contribute to that but, it's easy to see why someone who went through an experience like this one might be convinced it's the only way to coach software developers.