Is there a role-based structure that is used to authorize access to the application?

Answer:

Yes. Global Account Admins have access to all data within an account and can configure granular access permissions on a per calendar (hierarchical) basis to users. Roles are associated with Calendars and include: Parent Calendar Admin (Enterprise-only role), Editor, Contributor, Internal Reviewer, and External Reviewer.

Roles can be customized for an individual user per calendar. A user may be an Editor on Calendar A and have no access or any other role on Calendar B.