Which document establishes requirements for conducting background investigations for the five-tiered investigative model?

The correct answer is the document that provides a comprehensive framework for conducting background investigations within the five-tiered investigative model. Federal Investigative Standards establish the specific requirements and guidelines necessary for conducting investigations that assess an individual's suitability for access to classified information or for employment in sensitive positions. This set of standards forms the basis for ensuring that investigations are consistent, thorough, and uniformly applied across different agencies.

In the context of personnel security, these standards help organizations determine how to assess the integrity, reliability, and trustworthiness of individuals in a systematic way. They ensure that the investigative processes align with national security policies and address the varied levels of risk associated with different clearance tiers.

While other documents mentioned, such as Executive Order 13467, DOD Manual 5200.02, and SEAD 6, play important roles in the broader context of personnel security and the establishment of guidelines for investigations, it is the Federal Investigative Standards that provide the specific operational requirements for conducting background investigations in a tiered framework.