The Quadrennial Defense Review is a Congressionally-mandated review of DOD strategy and priorities, establish in the National Defense Authorization Act (NDAA) for Fiscal Year 1997. The NDAA requires the Secretary of Defense to conduct a comprehensive examination (to be known as a “quadrennial defense review”) of the national defense strategy, force structure, force modernization plans, infrastructure, budget plan, and other elements of the defense program and policies of the United States with a view toward determining and expressing the defense strategy of the United States and establishing a defense program for the next 20 years. Each such [QDR] shall be conducted in consultation with the Chairman of the Joint Chiefs of Staff.
There have been four previous QDRs - 1997, 2001, 2006, 2010 - the 2014 QDR was the third QDR conducted during wartime.
The current 2014 Quadrennial Defense Review can be found at:
QDR 2014: http://archive.defense.gov/pubs/2014_Quadrennial_Defense_Review.pdf
A useful two-page fact sheet:
http://archive.defense.gov/pubs/20140302_FINAL_QDR_Fact_Sheet_v13_CLEAN.pdf
Statement by Secretary of Defense Chuck Hagel regarding the release of the FY 2015 Budget and 2014 QDR on March 4, 2014:
http://archive.defense.gov/releases/release.aspx?releaseid=16568
Other press stories relating to QDR 2014:
http://archive.defense.gov/home/features/2014/0314_sdr/qdr.aspx
Secretary Hagel and Congress constituted an independent panel to review the QDR as part of the National Defense Authorization Act of 2015. The Panel is composed of 10 national security and defense experts and retired senior military leaders. The SecDef appointed the co-Chairs, while the House Armed Services Committee (HASC) and Senate Armed Services Committee each nominated four members.
Former Secretary of Defense William J. Perry and General John P. Abizaid (Ret) served as co-chairs on the Panel. Their report "Ensuring a Strong U.S. Defense for the Future -- The National Defense Panel Review of the 2014 Quadrennial Defense Review can be read at: