A Vital Omission
A process step for benefits realization is missing. Although the topic of business benefits appears several times throughout the introduction and tools and techniques chapters, it is quite remarkable that the process section does not contain a respective process step. Indeed, it does not even mention anything about benefits realization.
Thus, the standard does not contribute to resolving the following issue: Does the organization try to track and review the benefits to validate the assumptions and business cases upon which projects and programs have been started?
This is a vital omission. This question cannot be answered by the discipline of project management because, by the time when benefits data can be gathered, the project has been closed and the project manager has been discharged. Therefore, the product life cycle phases coming into play after project closure have to be considered when reviewing benefits.
It seems that without collecting data generated after the product launch and deployment of project deliverables and, to the extent possible, feeding it back to the project portfolio management process, the organization's responsibility is not complete. Without such feedback the organization is not able to evaluate to what extent the intended benefits from the projects in the portfolio have actually been obtained. And the organization generally cannot become a real "learning organization", especially in the areas of business cases, project sponsorship, product launch and operations.
At the time the PMI standard was published, the final report of a UK government-funded research network,  has highlighted "principal areas in which new thinking is needed to guide practitioners in the management of projects". One of the principal areas identified in the report shifts the prime focus from product creation to value creation is. Controlling the realization of business benefits through PPM, then, is a practical application of the announced new thinking and of how to focus more on value creation.
8. Mark Winter and Charles Smith, EPSRC Network 2004-2006: Rethinking Project Management - Final Report, UK's Engineering and Physical Sciences Research Council, May 2006. Details can be found at www.rethinkingpm.org.uk
9. Mark Winter, Charles Smith, Peter Morris, Svetlana Cicmil: Directions for future research in project management: The main findings of a UK government-funded research network, in: International Journal of Project Management Vol. 24 Issue 8, November 2006, p. 638-649