The Project Management Office (PMO) is defined as the central unit within an organization to control project management and maintain project management systems.
However, in practice, three different types of a PMO can be identified:  

 
The Strategic PMO manages strategic goals of the organization and supports the selection of future projects by providing measures to rank potential projects according to their value contribution to the strategy. Additionally, this type of PMO focuses on continuous improvement and global standardization of professional project management within the organization. Most often this PMO is part of departments like “Business Development” and reports directly into the top management.

In contrast, Project Monitoring PMO specializes in project controlling. This type of PMO performs controlling of all projects globally and reviews them according to time, achievement of objectives, cost and quality. Even though this might not be the most effective way, very often you can find this in the Finance Department. By nature, this always puts focus on monitoring Budgets and Actual Costs.

As a third form, the Operational PMO undertakes supporting activities for various projects. The main task lies within the coordination of interfaces between projects, project manager development and administration in the PM system of an organization. Most often, a pool of project managers reports into the operational PMO within line management.

However, all mentioned types of PMOs need to be distinguished from pure single-project assistance which is limited to supporting activities for a single project or single program only and would be named a Project or Program Office. From an organizational perspective as well as in terms of scope of work and responsibility, PMOs and Project/Program Offices differ substantially but are mixed up at times.

Concluding, regardless of the name or type of PMOs, it is most important to have a PMO defined at all to ensure someone within the organization is taking the responsibility for professional project management. Evolving and redefining the PMO’s scope need to follow hereafter and, of course, is crucial to make the organizational Project Management a success.