The federal government uses three security clearance levels — Confidential, Secret, and Top Secret — and the difference between them is the damage that unauthorized disclosure would cause to national security. Executive Order 13526 sets those definitions, and about 4 million people hold one of the three at any given time.1White House Archives. Executive Order 13526 – Classified National Security Information Additional access categories like Sensitive Compartmented Information sit on top of a Top Secret clearance to further restrict who sees the most closely guarded material.
What Each Level Means
Every piece of classified information is placed into one of three tiers, and the adjective in each definition is what separates them.
- Confidential. Information whose unauthorized release could reasonably be expected to cause damage to national security.
- Secret. Information whose unauthorized release could reasonably be expected to cause serious damage to national security.
- Top Secret. Information whose unauthorized release could reasonably be expected to cause exceptionally grave damage to national security.
A person cleared at a higher level can generally access material at lower levels, but access always depends on a demonstrated need to know the specific information. Holding a Top Secret clearance does not entitle you to see every Top Secret document in the government. In practice, most agencies simply grant a Secret clearance rather than a Confidential one, because the investigation is identical and Secret offers more flexibility for future assignments.
How You Get Sponsored
You cannot apply for a clearance on your own. A federal agency or a government contractor working on classified programs must sponsor you, usually because a job you have been offered or assigned requires access to classified material. The sponsor initiates the investigation and the government covers the cost.
Once sponsored, you complete Standard Form 86, a detailed questionnaire that covers roughly ten years of your life.2Office of Personnel Management. Questionnaire for National Security Positions (SF-86) The SF-86 asks about residences, employment, education, foreign contacts, financial obligations, criminal history, drug use, mental health history, and personal references who can speak to your character over at least the past seven years. Accuracy is essential. Inconsistencies or omissions on the SF-86 are among the most common reasons clearances stall or get denied. Investigators are looking for honesty and reliability, not a spotless past.
What the Investigation Looks Like at Each Level
After you submit the SF-86, the Defense Counterintelligence and Security Agency runs a background investigation whose depth is tied to the clearance level the job requires.
Tier 3 for Confidential and Secret
Confidential and Secret both trigger a Tier 3 investigation.3Defense Counterintelligence and Security Agency. Federal Investigative Standards for Tier 3 and Tier 3 Reinvestigation That involves criminal database checks, verification of employment records, a credit review, and outreach to references. Investigators may also contact former employers and local law enforcement in places you have lived. Processing time for a Secret clearance typically runs 60 to 150 days, with complicated cases running longer.
Tier 5 for Top Secret
Top Secret requires a Tier 5 investigation, formerly known as a Single Scope Background Investigation. This is a substantially deeper look. Federal investigators conduct in-person interviews with neighbors, coworkers, friends, and personal references to build a picture of your character, habits, and vulnerabilities. They are looking for patterns that could make you susceptible to coercion: financial problems, substance abuse, undisclosed foreign contacts, or a history of dishonesty. Tier 5 investigations average 120 to 240 days.
SCI, SAPs, and Access Above Top Secret
Sensitive Compartmented Information and Special Access Programs are not separate clearance levels. They are additional access controls layered on top of a Top Secret clearance. Even with a Top Secret, you cannot view SCI or SAP material until you have been specifically approved for that compartment or program.
SCI generally protects intelligence sources and methods. Gaining SCI access requires an additional adjudication that often includes a counterintelligence polygraph. If approved, you are formally read in during a security indoctrination briefing and sign a Sensitive Compartmented Information Nondisclosure Agreement, Form 4414.4Office of the Director of National Intelligence. Sensitive Compartmented Information Nondisclosure Agreement (Form 4414) That agreement binds you permanently. Even after you leave government service, anything you write drawing on SCI knowledge must go through a pre-publication security review.
SCI can only be discussed, processed, or stored inside an accredited Sensitive Compartmented Information Facility, a specially constructed room meeting strict physical and technical security standards set by the Director of National Intelligence.5Office of the Director of National Intelligence. Intelligence Community Directive 705 – Sensitive Compartmented Information Facilities You cannot take SCI material home, discuss it on an unsecured phone, or open it on a regular computer.
Special Access Programs work similarly but often protect military technologies, covert operations, or acquisition programs rather than intelligence sources. SAPs sometimes carry their own investigation requirements beyond what SCI demands.
Interim Clearances While You Wait
Because investigations take months, agencies sometimes grant an interim clearance so you can start work sooner. An interim is a provisional decision that allows limited access to classified material while the full investigation continues. The agency reviews your SF-86, runs initial criminal and financial checks, and looks for obvious red flags such as unresolved foreign influence or recent drug use.
Interim clearances are not guaranteed. Some agencies rarely grant them regardless of the applicant, and an interim denial does not mean your final clearance will be denied. It means the agency prefers to wait for a more complete record. Gaps, unexplained financial issues, or unexplained disclosures on the SF-86 make an interim less likely.
Continuous Vetting Replaces Periodic Reinvestigation
The government is changing how it monitors people who already hold a clearance. Under the Trusted Workforce 2.0 initiative, the old system of periodic reinvestigations at fixed intervals is being replaced by continuous vetting.6Defense Counterintelligence and Security Agency. Continuous Vetting Instead of waiting five, ten, or fifteen years to re-examine someone, DCSA runs automated checks against criminal, terrorism, financial, and public records databases on an ongoing basis throughout the person’s period of eligibility.7U.S. Government Accountability Office. Observations on the Implementation of the Trusted Workforce 2.0
When an automated check flags something, such as a new arrest, a foreign travel pattern, or a sudden change in financial records, DCSA investigators review the alert and decide whether further action is needed. That action can range from an interview to a full reinvestigation or clearance revocation. The National Background Investigation Services system is the IT backbone connecting these databases, with full deployment projected through fiscal year 2027.7U.S. Government Accountability Office. Observations on the Implementation of the Trusted Workforce 2.0
Moving a Clearance to a New Agency
Federal policy requires agencies to honor each other’s clearance determinations rather than forcing you to start over when you change jobs. This principle, known as reciprocity, is governed by Security Executive Agent Directive 7.8Office of the Director of National Intelligence. Security Executive Agent Directive 7 – Reciprocity of Background Investigations and National Security Adjudicative Determinations When you move, the receiving agency checks your eligibility in databases like the Defense Information System for Security or Scattered Castles. If your investigation is current and no new derogatory information has surfaced, the new agency should accept the prior adjudication.
Reciprocity has limits. Your clearance will not transfer if your investigation is more than seven years old, if you are seeking a higher level than you currently hold, if the new position requires a polygraph you have not taken, or if new information has emerged that raises security concerns. SCI and SAP access often requires separate adjudication and may not transfer even when the underlying Top Secret does.
If you leave a cleared position entirely, your clearance becomes inactive. It can generally be reactivated without a new full investigation if fewer than two years have passed and your background investigation is still within its validity period. After a longer gap, you will likely need a new investigation.
Public Trust Is Not a Clearance
Public Trust positions are sometimes confused with clearances, but they are a separate category. They apply to federal employees and contractors in roles involving public safety, health data, or significant financial oversight, and they do not authorize access to classified national security information.9USAJOBS Help Center. What Are Background Checks and Security Clearances Public Trust positions are designated Low Risk, Moderate Risk, or High Risk based on the potential impact of misconduct, and the vetting uses the SF-85 or SF-85P rather than the SF-86. If a position calls for Public Trust vetting, no security clearance level is involved.