Overview#Identity And Access Management may provide some relief for the issues with
Single-Sign-On utilizes a single credential store for the users identities. Applications and platforms utilize the single credential store for authentication.
Consistent-Sign-On utilizes Password Synchronization methodologies so the user only has one userID and one password to remember.
Reduced-Sign-On (RSO) is where Single-Sign-On (SSO) and or Consistent-Sign-On (CSO) has been implemented so there are fewer platforms or applications that require differeing credentials.
These methodologies are complementary and are typically implemented in all organizations to some level.