A security clearance is a determination that an individualâ€whether a direct federal employee or a private contractor performing work for the governmentâ€is eligible for access to classified national security information. A high-quality personnel security clearance process is necessary to minimize the risks of unauthorized disclosures of classified information and to help ensure that security-relevant information is identified and assessed. Chapter 1 provides a primer on some of the fundamental aspects of the security clearance process, using a "Frequently Asked Questions" format. Chapter 2 assesses the extent to which (1) ODNI has implemented an executive branch-wide program and developed plans to monitor and measure its performance; (2) DOD and other agencies have designed, piloted, and evaluated continuous evaluation and (3) agencies completed timely periodic reinvestigations from fiscal years 2012-2016, and the potential effects of continuous evaluation on reinvestigations. Chapter 3 focuses on the extent to which executive branch agencies (1) made progress reforming the security clearance process, and (2) are meeting timeliness objectives and reducing NBIB's investigative backlog. Chapter 4 discusses our government's security clearance process and potential areas of reform.