A comprehensive errata policy will inform users of both printed and Web-based publications when an error has been found and corrected. If an error is detected before an initial mailing, RRB includes an errata notice with the mailing. If the mailing has been sent out, an errata sheet is issued with all subsequent publications that are disseminated and, where appropriate, the errata sheet is sent to all those who received the initial mailing. Errata notices are placed on the first page of the Web version to inform both new and repeat site visitors about the mistake, and the corrected version of the document is posted on the Web.