The Quadrennial Defense Review (QDR) is a legislatively mandated review of Department of Defense (DOD) strategy and priorities. The QDR will set a long-term course for DOD as it assesses the threats and challenges that the nation faces and rebalances DOD’s strategies, capabilities, and forces to address today’s conflicts and tomorrow’s threats.
http://www.defense.gov/pubs/2014_Quadrennial_Defense_Review.pdf