Category: Personnel Vetting & Clearances

Investigation Tiers (Tier 1-5)

Also known as: Federal Background Investigation Tiers, Personnel Vetting Tiers, T1-T5, Tier 1, Tier 2, Tier 3, Tier 5, Tier 5 Reinvestigation (T5R)

Simply put

Investigation Tiers are the standardized levels of federal background investigation used to vet people for government jobs, contracts, and security clearances, ranging generally from Tier 1 for the most basic checks up to Tier 5 for the most thorough. The higher the tier, the more extensive the investigation. For example, Tier 1 covers low-risk, non-sensitive positions, while Tier 5 is used for the highest-sensitivity roles such as those requiring Top Secret access.

Formal definition

The Tier framework (T1 through T5, including reinvestigations such as T5R) is the tiered structure of federal personnel vetting investigations administered through the Defense Counterintelligence and Security Agency (DCSA), each tier corresponding to a position's risk and/or sensitivity designation and paired with a specified investigative form. Tier 1 is the baseline investigation for low-risk, non-sensitive positions and generally requires a National Agency Check with associated record searches; it should not be characterized as a national-security or public-trust investigation. Tier 5 (formerly the Single Scope Background Investigation, or SSBI) is a field-driven investigation used for the highest-sensitivity access, such as Top Secret and TS/SCI, with Tier 5 Reinvestigation (T5R) used for periodic reinvestigation. This entry does not enumerate the full scope, coverage periods, or specific form numbers for each tier, and it does not address how tier assignment maps to position designation in a given agency; readers should verify current tier requirements, applicable forms, and position-designation criteria against current DCSA and OPM authoritative guidance, as investigation standards, tier definitions, and continuous-vetting requirements are subject to change.

Why it matters

The Investigation Tier framework determines how thoroughly a person is vetted before being placed in a federal position or granted access to sensitive information, and getting the tier assignment right is foundational to both personnel security and regulatory compliance. Assigning a position to too low a tier can leave a high-sensitivity role filled by someone who has not undergone the appropriate scrutiny, while over-designating a position can impose unnecessary cost and delay. Because each tier corresponds to a position's risk and/or sensitivity designation and is paired with a specific investigative form, errors in position designation propagate directly into which investigation is conducted.

A common and consequential mistake is conflating investigation tiers with clearance status, or treating a completed investigation as a permanent qualification. An investigation supports an adjudicative decision; it is not itself a clearance, and the two should not be equated. Similarly, the highest tier, Tier 5 (formerly the Single Scope Background Investigation), is used for the most sensitive access such as Top Secret and TS/SCI, but it is subject to periodic reinvestigation through the Tier 5 Reinvestigation (T5R) process and, increasingly, to continuous-vetting requirements. Personnel security programs that assume a Tier 5 result remains valid indefinitely misunderstand how the framework is intended to operate.

For compliance officers and contractors, tier assignment also carries administrative and contractual weight: the wrong tier can stall onboarding, invalidate access grants, or trigger audit findings. Because tier definitions, applicable forms, coverage periods, and continuous-vetting expectations are subject to change under DCSA and OPM guidance, organizations should treat the framework as a living standard and verify current requirements rather than relying on historical practice.

Who it's relevant to

Personnel Security Specialists and Facility Security Officers

These practitioners initiate and track background investigations and must ensure each individual is submitted for the tier that matches their position's risk and/or sensitivity designation. They should treat completed investigations as inputs to adjudication rather than as clearances, and account for reinvestigation and continuous-vetting obligations, particularly for Tier 5 personnel.

Human Resources and Hiring Officials

HR staff designating positions and onboarding new federal employees and contractors need to understand that Tier 1 applies to low-risk, non-sensitive roles, while higher tiers correspond to more sensitive access. Correct position designation upstream determines the required investigation and form, and mis-designation can delay onboarding or result in an inappropriate level of vetting.

Government Contractors and Program Managers

Contractors filling roles that require access to sensitive information must plan for the investigation tier tied to each position, including the lead time and periodic reinvestigation associated with high-sensitivity roles such as those requiring Tier 5 for Top Secret or TS/SCI access. Program managers should verify current tier and form requirements against DCSA guidance rather than assuming prior standards still apply.

Compliance Officers and Auditors

Those reviewing personnel security programs should confirm that tier assignments align with position designations, that investigations are current, and that reinvestigation and continuous-vetting requirements are being met. They should flag common errors such as equating an investigation with a clearance or treating a Tier 5 result as permanently valid.

Inside Investigation Tiers (Tier 1-5)

Tiered Investigation Model

A framework, established under the Federal Investigative Standards and administered by agencies such as OPM and DCSA, that aligns the depth and scope of a background investigation to the risk and sensitivity level of a given position. The tiers generally range from Tier 1 through Tier 5, with higher tiers corresponding to greater sensitivity and more extensive investigative coverage. Readers should verify current tier definitions against authoritative DCSA and OPM sources, as position designations and investigative requirements are subject to update.

Tier 1

Generally applies to low-risk, non-sensitive positions and is commonly associated with HSPD-12 credentialing (Personal Identity Verification). Tier 1 is the least extensive investigation type and does not, by itself, correspond to national-security or public-trust position designations. Confirm the current scope of Tier 1 investigations against official DCSA/OPM guidance.

Tier 2

Generally associated with moderate-risk public trust positions. It typically provides broader coverage than Tier 1. The precise scope should be confirmed against current authoritative sources, as requirements can change across revisions of the Federal Investigative Standards.

Tier 3

Generally used for non-critical-sensitive national security positions, including certain personnel requiring access at lower national-security sensitivity levels. Specific eligibility and coverage details should be verified against current DCSA/OPM guidance.

Tier 4

Generally associated with high-risk public trust positions. It typically involves more extensive investigative elements than lower public-trust tiers. Confirm the current requirements against authoritative sources.

Tier 5

Generally used for critical-sensitive and special-sensitive national security positions, including those requiring access to the most sensitive information. Tier 5 is the most extensive investigation type in the model. Verify current scope and eligibility criteria against official DCSA/OPM publications.

Position Designation as the Trigger

The applicable tier is generally determined by the risk and sensitivity designation assigned to a position rather than by the individual, meaning the investigation scope follows how the position is categorized. Position designation practices should be confirmed against current authoritative guidance.

Common questions

Answers to the questions practitioners most commonly ask about Investigation Tiers (Tier 1-5).

Is Tier 1 the investigation used for low-risk national security or public trust positions?

No. Tier 1 generally applies to low-risk, non-sensitive positions and is commonly associated with HSPD-12 credentialing for physical and logical access, rather than to national security or public trust designations. Public trust positions are typically covered by other tiers (for example, Tier 2 for moderate-risk and Tier 4 for high-risk public trust), and national security positions are addressed under the tiers associated with access to classified information. Because position designation drives the applicable tier, readers should confirm the correct tier against current OPM and DCSA guidance and the specific position sensitivity and risk designation.

Does completing a favorable investigation at a given tier mean a person is cleared and can access classified information?

Not necessarily. An investigation is the fact-gathering process; it is distinct from the adjudication and the resulting eligibility or clearance determination. A completed investigation must be adjudicated against the applicable standards before eligibility is granted, and eligibility for national security access is separate from being read into or granted access to a specific classified program. Readers should distinguish the investigation tier, the adjudicative decision, and the access authorization, and verify each step against current authoritative guidance.

How is the appropriate investigation tier determined for a specific position?

The applicable tier generally follows from the position's risk and sensitivity designation, which the employing organization assigns based on duties and access requirements. In most implementations, non-sensitive low-risk positions map to Tier 1, while higher-risk public trust and national security positions map to higher tiers. Because designation methodology and tier mapping are governed by OPM and, for defense, DCSA guidance, organizations should confirm the current designation criteria and any agency-specific interpretations before initiating an investigation.

Do investigation tiers require periodic reinvestigation, or is an initial investigation sufficient?

Investigation tiers are generally not one-time events. Many positions are subject to reinvestigation or ongoing vetting requirements, and the government has been transitioning toward continuous vetting models in place of fixed periodic reinvestigation cycles for certain populations. The specific reinvestigation or continuous evaluation obligations depend on the tier, the position, and current policy, so readers should verify the applicable requirements against current OPM and DCSA guidance rather than assuming a static interval.

Which forms are typically associated with initiating an investigation at different tiers?

Investigation requests are generally submitted using standardized questionnaires appropriate to the position's risk and sensitivity level, with different forms historically associated with non-sensitive positions versus positions requiring access to sensitive or classified information. Because form designations, electronic submission systems, and case type mappings are maintained by DCSA and OPM and are subject to change, readers should confirm the current required form and submission process for the specific tier and case type rather than relying on legacy form names.

Who conducts and adjudicates these investigations across the tiers?

In most current implementations, background investigations across the tiers are conducted by the responsible federal investigative service provider, while adjudication is performed by the cognizant adjudicative authority for the employing organization or, for defense, the applicable consolidated adjudication function. The conduct of the investigation and its adjudication are distinct responsibilities and may reside with different entities. Because organizational responsibilities have shifted over time, readers should verify the current investigative service provider and adjudicative authority applicable to their organization.

Common misconceptions

Tier 1 covers low-risk national security or public trust positions.

Tier 1 generally applies to low-risk, non-sensitive positions and is commonly tied to HSPD-12 credentialing. It does not, by itself, correspond to national-security or public-trust designations, which are generally addressed by higher tiers.

A higher tier number is simply a formality and any tier can be used interchangeably for a given role.

The tier is generally driven by the position's risk and sensitivity designation. Using a lower tier than the position designation requires would not satisfy the applicable investigative standard; the tier and the position designation must align.

Completing a background investigation is the same as being cleared or authorized for access.

An investigation supports an adjudicative determination but is distinct from it. The investigation gathers information, while eligibility is generally decided through a separate adjudication process, and access may further depend on need and other requirements.

Best practices

Determine the correct tier based on the position's risk and sensitivity designation, and confirm that the designation itself is current and correctly assigned before initiating an investigation.

Verify the applicable tier definitions, coverage, and eligibility criteria against current authoritative DCSA and OPM sources, since the Federal Investigative Standards and position-designation guidance are subject to revision.

Do not treat Tier 1 as covering national-security or public-trust positions; reserve it for low-risk, non-sensitive positions and associated HSPD-12 credentialing purposes.

Distinguish clearly between the investigation (fact-gathering) and the adjudicative determination (eligibility decision) in policy, documentation, and communications with stakeholders.

Coordinate position designations with human resources, security, and hiring officials early so the appropriate tier is selected before onboarding and avoid rework from under- or over-designating positions.

Where interpretations are agency-specific or evolving, consult official DCSA/OPM guidance and confirm requirements rather than relying on prior practice.