Confidential or unidentified sources

National Geographic disfavors and avoids using unidentified sources. 

Only senior editors may approve the use of an unidentified source when news value warrants it and the information involved cannot be obtained in any other way. An unidentified source should not be the sole basis for a story except in extraordinary situations approved by the Editor in Chief. You must reveal all of your sources to your editor and, if applicable, relevant senior management of NGP. Personal attacks by unidentified sources are not allowed.

If an exception is made, explain in the story why the source is unnamed. It is preferable to characterize them by their role or other relevant descriptor and state that they wished to remain anonymous or declined to be identified (and the reason, if not obvious). The source, in rare cases, could be identified by first name only. Exceptions have been made in order to protect the safety of an individual, such as an underage bride, or in cases where immigration status may be jeopardized. If an anonymous source appears throughout a story, their initials may also be used.