The Central Intelligence Agency offers a wide range of opportunities for those wanting to serve in the agency's national security and intelligence missions. However, the critical and sensitive nature of CIA work requires that all employees obtain security clearances to ensure candor, character, reliability and overall suitability to access classified information. The CIA grants different levels of security clearances to employees corresponding to the sensitivity and risk level of classified information needed to perform essential duties.

Confidential Level

Of all clearance levels required by the CIA, the "Confidential" level is the most minimal clearance and the simplest to obtain. Classified information with a "Confidential" designation, such as personal data files, would carry risks to national security if divulged. However, the risk potential would be lower in comparison with information bearing higher classifications. The investigation process to obtain a Confidential clearance spans back to five years of employment, educational, criminal, financial and medical history and is reinvestigated every 15 years.

Secret Level

The "Secret" clearance level is designated to CIA employees to access classified information that would cause potentially grave damage to national security if divulged to the wrong parties. An investigation for a Secret clearance often spans back over 10 years of personal history and needs to be reinvestigated every 10 years.

Top Secret Level

The "Top Secret" clearance level is the highest and most difficult security clearance for CIA officers to obtain. However, most positions in the CIA, including agent, investigator or asset, require a Top Secret clearance. A Top Secret clearance requires an extensive background investigation going back to the candidate's 18th birthday and needs to be reinvestigated every five years once granted. As unauthorized divulgence of Top Secret information would pose an exceptional threat to national security, CIA officers are typically required to pass a Single Scope Background Investigation polygraph examination to verify background information prior to being granted a Top Secret clearance.

Top Secret/SCI Level

The "Top Secret/SCI" level -- or Top Secret with access to sensitive compartmentalized information -- holds similar investigative requirements and access rights to Top Secret, but it is more specialized. CIA officers already holding a Top Secret clearance would need an internal agency nomination to a particular position that requires SCI special access. In other words, information bearing an SCI classification is so highly sensitive that only those with agency-sanctioned need-to-know clearance can access them, excluding even personnel with normal Top Secret clearances.