The Tier 3 investigation is designated for which positions?
The Tier 3 investigation is designated for non-critical sensitive national security positions, including those requiring Confidential, Secret, or "L" access eligibility. It is the standard background investigation used to grant and maintain a Secret-level security clearance.
The answer
Under the federal government's Tiered investigation model (administered by the Defense Counterintelligence and Security Agency and OPM), Tier 3 is the investigation for non-critical sensitive national security positions. In practice, this means any position that requires eligibility for a Confidential or Secret clearance, or "L" access (the Department of Energy equivalent for Secret-level nuclear information).
If a job requires access to information classified at the Secret level, the person filling it must favorably complete a Tier 3 investigation. There is a companion product, the Tier 3R, which is the periodic reinvestigation used to keep an existing Secret clearance current. So the short version an exam wants is: Tier 3 = non-critical sensitive positions = Secret/Confidential/L clearance.
How the tiers fit together
The five-tier system replaced the older alphabet soup of investigation names (NACLC, ANACI, SSBI, etc.). Each tier maps to a position sensitivity or risk level:
- Tier 1 covers non-sensitive, low-risk positions and basic HSPD-12 credentialing (a building/logical-access badge).
- Tier 2 covers non-sensitive public trust positions at the moderate-risk level.
- Tier 3 covers non-critical sensitive national security positions — Confidential, Secret, and L access.
- Tier 4 covers public trust positions at the high-risk level.
- Tier 5 covers critical sensitive and special sensitive positions — Top Secret, SCI, and Q access.
Notice that odd-numbered tiers (1, 3, 5) run along the national security / sensitivity track while the even tiers (2, 4) run along the public trust / suitability track. Tier 3 sits squarely in the middle of the security track, which is exactly why it is tied to Secret rather than Confidential-only or Top Secret.
Why the other tiers are wrong
A common distractor is Tier 1, but Tier 1 is only for low-risk, non-sensitive jobs and credentialing — it grants no clearance at all. Tier 2 and Tier 4 are public-trust investigations; they concern whether someone can be trusted in a position that could affect the integrity of government operations, not whether they can access classified national-security information, so they never grant a Secret clearance. Tier 5 is the deepest investigation and is reserved for critical-sensitive positions requiring Top Secret or SCI access; using Tier 5 for a Secret-only position would over-investigate and misuse resources.
The reinvestigation cycle is worth knowing too: Secret clearances were historically reinvestigated (via Tier 3R) about every 10 years, and Top Secret (Tier 5R) about every 5 years. Both are increasingly folded into Continuous Vetting, which monitors cleared personnel in near-real time rather than waiting for a scheduled reinvestigation. That modernization is the context most answer-key snippets leave out.
| Tier 1 | Non-sensitive, low risk (HSPD-12) | Credential / badge only | N/A |
| Tier 2 | Public trust, moderate risk | Suitability (no clearance) | ~5 yrs |
| Tier 3 | Non-critical sensitive | Confidential / Secret / L | ~10 yrs (Tier 3R) |
| Tier 4 | Public trust, high risk | Suitability (no clearance) | ~5 yrs |
| Tier 5 | Critical/special sensitive | Top Secret / SCI / Q | ~5 yrs (Tier 5R) |
Frequently asked
What clearance does a Tier 3 investigation grant?
A favorable Tier 3 investigation supports eligibility for a Confidential or Secret security clearance, as well as Department of Energy "L" access. It is the standard investigation for the Secret level.
What is the difference between Tier 3 and Tier 5 investigations?
Tier 3 covers non-critical sensitive positions and supports a Secret clearance, while Tier 5 is a far more thorough investigation for critical-sensitive positions requiring Top Secret, SCI, or Q access. Tier 5 includes subject interviews and broader record checks that Tier 3 does not.
How often is a Tier 3 reinvestigation required?
Historically, Secret clearances were reinvestigated via the Tier 3R roughly every 10 years. Today most cleared personnel are enrolled in Continuous Vetting, which monitors them continuously instead of relying on a fixed reinvestigation date.
Who needs a Tier 3 background investigation?
Anyone appointed to a non-critical sensitive national security position — that is, a job requiring access to Confidential or Secret classified information (or DOE L access) — must complete a Tier 3 investigation before being granted the clearance.