Published 2026-01-10
Security Clearance Levels Explained
What Is a Security Clearance?
A security clearance is a status granted by the U.S. government that allows a person to access classified national security information. It's essentially the government saying: "We've investigated your background, and we trust you to handle sensitive information responsibly."
Clearances exist because the government needs people—both federal employees and private contractors—to work on projects involving information that could harm national security if it got into the wrong hands. Before anyone can see that information, the government wants to know: Can this person be trusted? Are they loyal to the United States? Are they vulnerable to bribery, blackmail, or foreign influence?
The investigation and adjudication process is how they answer those questions.
Why Are There Different Levels?
Not all classified information is equally sensitive. Some information, if leaked, might cause embarrassment or minor setbacks. Other information could compromise intelligence sources, reveal military capabilities, or get people killed.
The U.S. government uses three clearance levels to match the sensitivity of information with the depth of investigation required[1]. The more potentially damaging the information, the higher the clearance level needed to access it—and the more thorough the background investigation.
Think of it as a ladder: each level grants access to more sensitive material, but requires more scrutiny to obtain.
The Three Clearance Levels
Confidential
- Damage if disclosed: Could cause damage to national security[1]
- Investigation: National Agency Check with Law and Credit (NACLC)
- Reinvestigation: Every 15 years[2]
- Common roles: Entry-level contractor positions, some military roles
Secret
- Damage if disclosed: Could cause serious damage to national security[1]
- Investigation: National Agency Check with Law and Credit (NACLC)
- Reinvestigation: Every 10 years[2]
- Common roles: Most defense contractors, military personnel, government employees
Top Secret
- Damage if disclosed: Could cause exceptionally grave damage to national security[1]
- Investigation: Single Scope Background Investigation (SSBI)
- Reinvestigation: Every 5 years (now transitioning to Continuous Vetting)[3]
- Common roles: Intelligence, senior military, sensitive programs
Beyond Clearance Levels
SCI (Sensitive Compartmented Information)
Not a clearance level, but an additional access category. Requires Top Secret clearance plus compartment-specific approval.
SAP (Special Access Programs)
Programs with additional security requirements beyond standard classification levels.
Related
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References
- ^ Executive Order 13526: Classified National Security Information. National Archives. Accessed 2026-01-08.
- ^ DoDI 5200.02: DoD Personnel Security Program. Department of Defense. Accessed 2026-01-08.
- ^ DCSA Continuous Vetting. Defense Counterintelligence and Security Agency. Accessed 2026-01-08.