bureau checks, and written inquiries to current and former employers covering a 5-year period. BACKGROUND INVESTIGATION. —DIS conducts a background investigation (BI) to gather  information  on  a  person’s  loyalty, character,  emotional  stability,  and  reliability. It consists of an NAC plus a field investigation consisting of an interview and a written inquiry. Standard BI elements include checks of employ- ment; education; organization affiliations; local agencies; where the subject has lived, worked, or gone to school; and interviews with persons who know the individual. Depending on the informa- tion disclosed, the BI may also include credit and neighborhood checks and an interview of the subject to resolve any questionable or derogatory information. The scope of a BI usually covers a period that extends back 5 years or begins at the 18th birthday, whichever is the shorter period; however, at least the last 2 years are covered, with the exception that no investigation is conducted before a person’s 16th birthday. No time limit is  set  for  the  resolution  of  questionable  or derogatory information. The scope of a BI for persons assigned to NATO billets and for non-U. S. citizens is 10 years (with the restriction on investigation before the 16th birthday). A full field investigation (FFI) conducted by the FBI or OPM is the equivalent of a BI. SPECIAL  BACKGROUND  INVESTIGA- TION. —A special background investigation (SBI), conducted by DIS, extends coverage of the person’s background to provide a greater depth of knowledge than a standard BI. An SBI includes an NAC on the member’s spouse or cohabitant. It also includes an NAC on any immediate family members 18 years of age or older who are U.S. citizens other than by birth or who are not U.S. citizens. The scope of an SBI covers a period that extends back 15 years or begins at the 18th birthday, whichever is the shorter period; however, at least the last 2 years are covered, with the exception that no investigation is conducted before the person’s 16 birthday. At the present time, CNO authorizes SBIs only on personnel who have access to certain information or who are assigned  to  certain  duties.  The  following assignments presently require an SBI: Assignments requiring access to single inte- grated operational plan—extremely sensitive information   (SIOP-ESI) Assignments  requiring  access  to  sensitive compartmented  information  (SCI) Assignment to Presidential support duties Assignment to investigative agencies as special agents  or  investigative  support  personnel requiring continuous access to investigate files and materials PERIODIC REINVESTIGATION. —A periodic reinvestigation (PR) updates a valid investigation conducted by DIS. It consists of a personal interview, an NAC, local checks, credit checks, and interviews with employment references and character references. A periodic reinvestigation also includes a command review of all available records when warranted by the facts of the case. SPECIAL INVESTIGATIVE INQUIRY. —A special investigative inquiry (SII), conducted by DIS, has two purposes. The first purpose is to prove or disprove allegations about a person on whom a personnel security determination has been made. The second is to assess the current eligibility of an individual on whom an unfavorable person- nel security determination had previously been made. An SII consists of a limited inquiry, a post-judicatory  investigation,  or  some  other type  of  DIS  inquiry.  SIIs  do  not  investigate current criminal activity, sabotage, espionage, or subversion. The Naval Security and Investigative Command investigates those matters. Since SIIs supplement the basic PSI, they are not entered as investigations on the Certificate of Personnel Security Investigation Clearance and Access  (OPNAV  Form  5520/20). The Nuclear Weapons Personnel Reliability Program Investigative requirements for the Nuclear Weapons Personnel Reliability Program (PRP) are based on the sensitivity of the position occupied. The position may or may not reflect the classification level of information to which the person may have access. Positions in the PRP are designated as Critical or Controlled. A Critical position in the PRP requires a BI within the past 5 years before initial assignment. Continued assignment to a PRP position is allowed without an update of the investigation. 9-42