People usually work on more than one project for more than one project manager. If each project manager creates a resource to represent the same worker in each Project file, overallocated resources and resource squabbles are soon to follow. The solution in Project Standard and Professional is a resource pool, which is a Project file dedicated to resource information—the pool of resources that work on projects, their cost, availability, and most important, how much they're already allocated to tasks.
The beauty of a resource pool is that resource information is in one place. Project managers who use those resources simply link their projects to the resource pool. Assigning resources works exactly as it does when resources are contained in the project file. The only difference is that you can see how much of the resources' time is allocated to tasks from all linked projects. (A resource pool in Project Standard and Professional follows the same idea as the enterprise resource pool in Project Server, although Project Server includes a few more tools for finding the right resources.)
The simplest way to set up a resource pool is to create a new Project file, which does nothing but act as a resource pool. Although you can use a Project file with tasks in it as the resource pool, you may run into problems if you want to work on the tasks and someone else wants to work on resource information.
If an existing project contains all ...