In a traditional sense, a chief of staff is hired at the direct report level to sit on strategy and C-suite meetings. They are expected to track progress and push toward quarterly and yearly goals. They know what KPIs to measure performance, who controls what, and what levers to push or pull to ensure expectations are met.
This is not the chief of staff that you would be employing with your EA – instead they would share the same type of knowledgebase that a traditional chief of staff would have.
Instead of flooding your inbox or voicemail with contacts, you can use your EA as a gatekeeper for the information. They will cut out many hours spent handling these contacts and calls by screening them ahead of time and handling the relevant ones to you personally.