Being a PM in a healthcare project that aims to deliver a GP Clinic Electronic Medical Record & Operation System with multiple external interfaces, I have to work with subject matter experts (SMEs) on several different streams due to the multi-disciplinary areas that are involved.
Each of these SMEs, assigned from other functional departments in a matrix setup, are driving their respective streams with the vendor.
To be effective in the management of the schedule and scope, its critical for the PM not to lose control on the progress of each stream. The PM should be able to build up the competency on each stream to a certain level fast and contribute effectively in the streams' discussions. Only with a fair amount of competency and "technical" knowledge in all the streams, the PM will be able to exert control and display creditability as the overall person responsible for the project.
Without being able to maintain control over the project, I have witnessed when all the stream leads attempt to lead the out-sourced vendor from different angles and the PM not able to manage and control the situation well. That contributes to the project complexity and risks as well as completely swings the vendor into position where they have to fulfill multiple different requests, thereby thinning their resources and losing control of the progress.
It is definetly a good sign when each SME taking the role as a stream lead proactively followup and push for their items to be achieved. However the PM needs to be able to convince, influence and value add as an overall person in charge of the project by effectively demonstrating he/she has a good understanding and knowledge of each streams' progress, issues, status and risks as well as an excellent integrated project view.
Only when there is one single, competent "cook", endorsed by the team to be made responsible for the project, can the vendor be well managed and the project progress smoothly in its schedule and scope.