Deputy Secretary of Defense Ashton Carter briefs the press at the Pentagon in Arlington, Va., on Sept. 25, 2013. Carter announced three reviews of security at Department of Defense installations in the wake of the Navy Yard shootings. The Office of the Secretary of Defense will lead one review and an independent panel will head another. These two reviews will focus on assessing the physical security and access at DoD installations to identify vulnerabilities. They will also examine the security clearance and reinvestigation process to identify any shortcomings and what steps to take to tighten the standards for granting and renewing a security clearance. The Department of the Navy is leading the third review, which will examine physical security at all Navy and Marine Corps installations worldwide.