As a system administrator, you must update your organization’s Salesforce user profiles to allow access for users who will run backlog calculations. Grant users access to the following:
In the Sharing Settings, if you choose Public Read for the Backlog Calculation object, this means if a user has access to some backlog data, they have access to all of it. You can set the value to Private, however, if a user who has no sharing access runs a backlog calculation, you cannot not view the backlog data they calculated unless it is explicitly shared with you.