A security clearance is a status that is granted to individuals, allowing them access to classified information (or restricted areas) after the completion of a thorough background check. It is an assurance that the person is able (and willing) to protect classified national security information. This can give a candidate a competitive advantage when job searching.
A security clearance is a valuable benefit. It affords a candidate a level of hiring preference with any government-sector employer (either civilian contractors or governmental agencies) that requires clearance.
According to ClearanceJobs.com in their 2013 annual Security Clearance Jobs Salary Survey:
“There is no shortage of the need for highly trained, skilled professionals in the intelligence and information technology communities that feed our policy makers with classified material that they require to make informed decisions.”