Hello! @Daniel Campbell
Welcome to the LastPass Community.
The security score in the admin console is based on an analysis of all the saved passwords in the vault, if the user has duplicated passwords or small passwords the security score will decrease, please ask the user to check the security score from the security tab in his vault and request to check the passwords.
Regarding the explanation by the time the user accesses the security score there is already a brief explanation about how it works.
Please let me know if you need additional help.
Greetings!
Verlaine | Customer Care