Security vs Suitability
A security clearance investigation is an inquiry into an individual's loyalty, character, trustworthiness and reliability to ensure that he or she is eligible for access to national security information.
"The Director of National Intelligence shall serve as the Security Executive Agent. As the Security Executive Agent the Director of National Intelligence shall direct the oversight of investigations and determinations of eligibility for access to classified information or eligibility to hold a sensitive position made by any agency; shall be responsible for developing uniform and consistent policies and procedures to ensure the effective, efficient, and timely completion of investigations and adjudications relating to determinations of eligibility for access to classified information or eligibility to hold a sensitive position."
–EO 13467
A suitability investigation is an inquiry into a person's identifiable character traits and conduct sufficient to decide whether an individual's employment or continued employment would or would not protect the integrity or promote the efficiency of the service.
"The Director of the Office of Personnel Management shall serve as the Suitability Executive Agent. As the Suitability Executive Agent, the Director of the Office of Personnel Management will be responsible for developing and implementing uniform and consistent policies and procedures to ensure the effective, efficient, and timely completion of investigations and adjudications relating to determinations of suitability and eligibility for logical and physical access."
–EO 13467
