The simplest security clearance to get. This level typically requires a few weeks to a few months of investigation. A Confidential clearance requires a NACLC investigation and must be renewed (with another investigation) every 10 years.
A Secret clearance, also known as Ordinary Secret, requires a few months to a year to fully investigate depending on the individual's activities. Some instances where individuals would take longer than normal to be investigated are many past residences, having residences in foreign countries, or have relatives outside the United States. Bankruptcy and unpaid bills as well as criminal charges will also increase the time of both the investigation and approval. A Secret clearance requires a NAC/LAC/Credit investigation and must be reinvestigated every 10 years.
Top Secret is a more stringent clearance. A Top Secret, or "TS", clearance, is often given as the result of a Single Scope Background Investigation, or SSBI. Top Secret clearances generally afford one access to data that affects national security, counterterrorism/counterintelligence, or other highly sensitive data. There are far fewer individuals with TS clearances than Secret clearances. A TS clearance can take as little as 3-6 months to obtain, but more often takes 6-18 months, while sometimes taking up to 3 years to obtain. The SSBI investigation must be reinvestigated every 5 years.
Sensitive Compartmented Information (SCI)
As with TS clearances, Sensitive Compartmented Information (SCI) clearances are assigned only after one has been through the rigors of a Single Scope Background Investigation. SCI access, however, is assigned only in "compartments." See Compartmentalization (intelligence). These compartments are necessarily separated from each other organizationally, so an individual with access to one compartment will not necessarily have access to another. Each compartment may include its own additional clearance process.
Compartments of SCI (incomplete list):
TK: Satellite intelligence
SI: Special intelligence (primarily intelligence organizations)
Q: Nuclear weapons
Such compartmentalized clearances may be expressed as "John has a TS/SCI TK/Q clearance", where all clearance descriptors are spelled out verbally. For example, The US National Security Agency appends Umbra to some top secret information. This classification is reported to be a compartment within the "Special Intelligence" compartment of SCI.
Certain government departments may also establish special access programs (SAP) when vulnerability of specific information is exceptional; and the normal criteria for determining eligibility for access applicable to information classified at the same level are not deemed sufficient to protect the information from unauthorized disclosure. The number of people cleared for access to such programs is typically kept low. Information about stealth technology, for example, often requires such access.
Requirements for a clearance:
The vetting process for a security clearance is usually undertaken only when someone is hired or transferred into a position that requires access to classified information. The employee is typically fingerprinted and asked to fill out a detailed life history form, including all foreign travel, which becomes a starting point for an investigation into the candidate's suitability. This process can include several types of investigations, depending on the level of clearance required:
National Agency Check with Local Agency Check and Credit Check (NACLC). An NACLC is required for a Secret, L, and CONFIDENTIAL access. (See: Background check)
Single Scope Background Investigation (SSBI). An SSBI is required for Top Secret, Q, and SCI access, and involves agents contacting employers, coworkers and other individuals. Standard elements include checks of employment; education; organization affiliations; local agencies; where the subject has lived, worked, or gone to school; and interviews with persons who know the individual. The investigation may include an NACLC on the candidate’s spouse or cohabitant and any immediate family members who are U.S. citizens other than by birth or who are not U.S. citizens.
Polygraph. Some agencies may require polygraph examinations. The most common examinations are Counter Intelligence (CI) and Full Scope (Lifestyle) polygraphs. While a positive SSBI is sufficient for access to SCI-level information, polygraphs are routinely administered for "staff-like" access to particular agencies.
If issues of concern surface during any phase of security processing, coverage is expanded to resolve those issues. At lower levels, interim clearances may be issued to individuals who are presently under investigation, but whom have passed some preliminary, automatic process. Such automatic processes include things such as credit checks, felony checks, and so on. An interim clearance may be denied (although the final clearance may still be granted) for having a large amount of debt or having admitted to seeing a doctor for a mental health condition.
Investigations conducted by one federal agency are no longer supposed to be duplicated by another federal agency when those investigations are current within 5 years and meet the scope and standards for the level of clearance required. The high level clearance process can be lengthy, sometimes taking a year or more. The long time needed for new appointees to be cleared has been cited as hindering U.S. presidential transitions.
The security clearance forms are available at http://www.gsa.gov/Portal/gsa/ep/formslibrary.do