Project Portfolio Management, or PPM, gives a company's top leadership the ability to track and evaluate the progress of disparate projects the organization is undertaking and make judgments on whether its resources are being wisely and effectively invested.
If you are trying to track the performance of your projects through traditional project management, you are pulling information out of the project files, trying to get data out of PowerPoint and e-mail. You are never going to be able to see everything at once. The data you do collect will be months late, and there's no assurance that it will be the data you need to make decisions on which projects deserve more investment and which are not worth pursuing.
Project Portfolio Management allows easy access to project data that allows your company to compare project status and performance, apples-to-apples. A PPM system can assure that project teams are fully aware of strategic goals and that the work being done is the work the company wants to be done.
Adoption of a PPM system is a long-term commitment to bring transparency to your company's project work. It will make project teams more accountable, but also free them to focus on the work that management is trying to accomplish. It should not be undertaken unless company leadership intends to use the best possible evidence to make important strategic decisions.