As your organization grows and learns to accept that projects need to be structured you need to make sure your staff understands what that structure is when they are running their projects.
Many organizations that reach this level have 2 types of projects. Small ones and big ones. What is small and what is big? It depends on your organization. You may choose a dollar amount to define them, or a project ranking system or some other means that fits your organization.
So what is in this manual?
The manual should detail the steps of the project from the beginning (like a method to review and accept new projects, so it stops the projects coming in the back door) to the end (how about a standard project close-out check list) and the forms and templates the PM must use to run the project. These forms and templates typically are specific to your organization.
Why standardize this process? Well, it will allow your PMs and team members to see one consistent way of managing projects. Also, your staff will spend less time fighting fires and it will limit things from slipping through the cracks.
Once you have this in place you can move on to the next phase which is auditing your PMs to make sure they are using your predefined methodology.
“Successful firms have mastered the art of melding the power of human will and organization. But the key to their vitality is their world class capabilities in selecting, guiding, and completing development projects, which are the building blocks of renewal and change. The companies that can repeat this process again and again have discovered the manufacturer’s perpetual motion machine”
Bowen, H. Kent, Clark, Kim B., Holloway, Charles A., Wheelwright, Steven C., The Perpetual Enterprise Machine, page 14 Oxford University Press, Inc. New York, NY., 1994.