Another benefit of focusing on outcomes is that it helps raise our credibility. People who create something are always seen as more valuable than people who just do something, especially if this is just to shuffle paper (even i-paper.)
The same applies to HR - we will be seen a more impact full if we talk about raising commitment or the skills of our sales forces, than if we talk about running communications briefings or training courses.
We need to focus on outcomes because that makes it more likely that we will talk about outcomes too.