Which tier of federal investigation replaced the Single Scope Background Investigation?

The correct answer is that the Single Scope Background Investigation (SSBI) was replaced by Tier 5 investigations. This change is part of the Continuous Evaluation (CE) initiative under the Trusted Workforce 2.0 security clearance reform, which streamlined the process for personnel security investigations. Tier 5 investigations are generally used for individuals granted access to Top Secret information and are designed to be more comprehensive than previous investigations, addressing both personal and professional aspects of a person's life that could indicate a potential risk.

In contrast, Tier 2 and Tier 3 investigations serve different purposes. Tier 2 is typically for Moderate Risk positions and focuses on verifying an individual's background over a shorter period, while Tier 3 is for High Risk positions and is less extensive compared to Tier 5. Tier 4 does not exist in the current investigation framework, making Tier 5 the definitive successor to the Single Scope Background Investigation.