The term was also commonly used inside NASA. They used it as a technique to help people better understand their relationship with themselves as well as others.

The idea of unknown unknowns was created in 1955 by two American psychologists, Joseph Luft and Harrington Ingham in their development of the Johari window. Rumsfeld's statement brought attention to the concepts of known knowns, known unknowns, and unknown unknowns, but national security and intelligence professionals have long used an analysis technique referred to as the Johari window. Known unknowns refers to 'risks you are aware of, such as canceled flights,' whereas unknown unknowns are risks that come from situations that are so unexpected that they would not be considered. The statement also features in a 2013 documentary film, The Unknown Known, directed by Errol Morris. In The Decision Book, author Mikael Krogerus refers to it as the 'Rumsfeld matrix'. The statement became the subject of much commentary. And if one looks throughout the history of our country and other free countries, it is the latter category that tends to be the difficult ones. But there are also unknown unknowns-the ones we don't know we don't know. We also know there are known unknowns that is to say we know there are some things we do not know.

Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns there are things we know we know. Department of Defense (DoD) news briefing on February 12, 2002, about the lack of evidence linking the government of Iraq with the supply of weapons of mass destruction to terrorist groups.

' There are unknown unknowns' is a phrase from a response United States Secretary of Defense Donald Rumsfeld gave to a question at a U.S. Rumsfeld during a Pentagon news briefing in February 2002

Source unknown