A factor that can derail progress on an improvement project is a lack of clarity around who is meant to be doing what.
When creating a formal project plan this is usually not an issue. You assign owner's to each element of the plan and it becomes crystal clear who is doing what.
The problem, as I see it, is when the project moves out of scope into less formal project areas. You know that something needs to be fixed / improved upon that is related to your project, but no one knows who is responsible for that area. This can obviously lead to confusion and delay if it is not agreed.
Having clarity around the business of who owns what process is vital. Communicating this formally is incredibly useful. Most times this kind of ownership is linked back to 'roles and responsibilities' type documents. For many people these are not visible documents and so a way around this is to create a family tree (organogram) to map out people's responsibilities.
If there are any gaps then you can fill them. If you get stuck looking for help then you find out who the right person is to speak to. It is a simple tool, but one that can save a lot of time and confusion down the line.
Author of 'Business Process Re-Engineering', a practical plan to improve business performance.