Understanding Role-based Security
The Reporting Services role-based security model is similar to the role-based security models of other technologies. Like the security models of other products, Reporting Services security is based on the premise that you can classify or categorize user interaction with a system or resources, and then map user or group accounts to those categories. For example, the System Administrator role is common to many role-based models and is assigned to users who have administrator privileges on a server.
A role-based security model grants end-user access to specific operations through role membership. All users who are members of a role can perform the operations that are defined for the role.
Role-based security is flexible and scalable, particularly when you use it with group accounts. You can map group accounts to role definitions, and then allow the changing membership of those groups to automatically adjust for new report users coming into the organization or moving to different positions in the organization, and other report users exiting the organization.