Which PSI is commonly used for non-US citizens requiring Limited Access Authorizations?

The correct answer for the question about which Personnel Security Investigation (PSI) is commonly used for non-US citizens requiring Limited Access Authorizations is the Single Scope Background Investigation (SSBI).

The SSBI is designed to be comprehensive, examining various aspects of an individual's background, including their personal life, work history, financial status, and foreign contacts. For non-US citizens, this investigation is particularly important as it helps assess any potential risks or affiliations that may raise concerns regarding national security. The depth of the SSBI allows for a thorough evaluation which is essential for individuals who may not have the same level of established background in the US as a citizen would, thus ensuring a robust security assessment.

Other investigations, while they serve their purposes, may not provide the same level of detail or comprehensive background analysis required for non-citizens. For example, the Access National Agency Check with Inquiries is primarily used for lower-level clearances and may not delve as deeply into an individual's history. The National Agency Check with Local Agency and Credit Checks focuses on specific aspects without the same level of comprehensive analysis. The Continuous Evaluation Program Investigation is intended for ongoing monitoring of individuals who already hold a clearance and is not a primary tool for initial investigations for non-citizens.