This report is based substantially upon work conducted for ongoing audits and previously completed GAO products, which were conducted in accordance with generally accepted government auditing standards or with GAO's quality assurance framework, as appropriate. We conducted the work for the overall report from February 2010 through February 2011. For issues being reported on for the first time, GAO sought comments from the agencies involved and incorporated those comments as appropriate. Appendix II contains additional details of our scope and methodology.