The term "Vaughn Index" originated from Vaughn v. Rosen, 484 F.2d 820 (D.C. Cir. 1973), cert. denied, 415 U.S. 977 (1974), wherein the court rejected an agency's conclusory affidavit stating that requested FOIA documents were subject to exemption. Id. at 828. "A Vaughn Index must: (1) identify each document withheld; (2) state the statutory exemption claimed; and (3) explain how disclosure would damage the interests protected by the claimed exemption." Citizens Comm'n on Human Rights v. FDA, 45 F.3d 1325, 1326 n.1 (9th Cir. 1995). This detailed affidavit " 'permit[s] the court system effectively and efficiently to evaluate the factual nature of disputed information.' " John Doe Agency v. John Doe Corp., 493 U.S. 146, 149 n.2 (1989) (quoting Vaughn, 484 F.2d at 826).