Project Management Offices (PMOs) are not etched in stone. They are complex entities which go through frequent transformations during their average two-year life span. So, what does that mean to project professionals? Identifying the Forces Driving Frequent Change in PMOs answers this question for both researchers and practitioners based on a three-year research effort focused on the organizational change process surrounding the transformation of a PMO. Seventeen case studies and 184 responses to a questionnaire provide the foundation. Results show the temporary nature of PMOs and reveal that significant changes in PMOs can be associated with an organization's internal and external environment.