"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. 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. Rumsfeld stated: The statement became the subject of much commentary. In The Decision Book, author Mikael Krogerus refers to it as the "Rumsfeld matrix". The statement also features in a 2013 documentary film, The Unknown Known, directed by Errol Morris. 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. Origins 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. 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. They used it as a technique to help people better understand their relationship with themselves as well as others. The term was also commonly used inside NASA. Rumsfeld cited NASA administrator William Graham in his memoir; he wrote that he had first heard "a variant of the phrase" from Graham when they served together on the Commission to Assess the Ballistic Missile Threat to the United States during the late 1990s. Kirk Borne, an astrophysicist who was employed as a data scientist at NASA Goddard Space Flight Center at the time, noted in an April 2013 TED talk that he had used the phrase "unknown unknowns" in a talk to personnel at the Homeland Security Transition Planning Office a few days prior to Rumsfeld's remarks, and speculated that the term may have percolated up to Rumsfeld and other high-ranking officials in the Defense Department. The terms "known unknowns" and "unknown unknowns" are often used in project management and strategic planning circles. Contemporary usage is largely consistent with the earliest known usages. For example, the term was used in evidence given to the British Columbia Royal Commission of Inquiry into Uranium Mining in 1979: The term also appeared in a 1982 New Yorker article on the aerospace industry, which cites the example of metal fatigue,