Administrative Processing

Security Advisory Opinion (SAO) or Washington Special Clearance, commonly called security clearance, administrative clearance, or administrative processing,is a process the United States Department of State and the diplomatic missions of the United States use in deciding to grant or deny a United States visa to certain visa applicants. The process involves sending a request from the visa issuing post to the Department of State's headquarters in Washington, D.C., to investigate an individual's case for possible espionage, terrorism, and illegal export of technology out of the United States.

Apart from the Department of State, the process involves other agencies of the federal government of the United States, specially those under Department of Homeland Security. Some of the agencied involved are: FBI, CIA, Drug Enforcement Agency, Department of Commerce, Department of Treasury's Office of Foreign Assets Control, Interpol, and the Department of State's Bureau of International Security and Nonproliferation.
The process for issuing a United States visa, possibly including a Visas Mantis check

SAOs have been the source of long delays for determining if a non-US citizen should be issued a US visa or not. As a result, United States Government Accountability Office found in a report dated February 2004 that "students and scholars with science backgrounds might decide not to come to the United States, and technological advancements that serve U.S. and global interests could be jeopardized" as a result.

In mid-2003, SAOs were submitted for about 2% of the applicants. The Department of State processed 245,000 SAOs in FY 2006, and has processed over a million SAOs in the period from September 2001 to May 2007.

Source: wikipedia