In a reply to criticisms of its World Trade Center investigation, the National Institute of Standards and Technology (NIST) admits that it is unable to fully explain the total collapse of the Twin Towers on 9/11. NIST’s letter is a response to a “request for correction” letter sent to it five months earlier by Bob McIlvaine and Bill Doyle, who both lost family members on 9/11, along with scientists Kevin Ryan and Steven E. Jones, architect Richard Gage, and the group Scholars for 9/11 Truth and Justice. This letter made several assertions about NIST’s final reports of its WTC investigation, and suggested they had violated the Data Quality Act and NIST’s information quality standards. NIST’s reply denies the requests for corrections. However, it also mentions, “[W]e are unable to provide a full explanation of the total collapse” of the World Trade Center. [National Institute of Standards and Technology, 9/27/2007 ] In its final report on the Twin Towers collapses, released in October 2005, NIST admitted that its investigation did “not actually include the structural behavior of the tower after the conditions for collapse initiation were reached and collapse became inevitable” (see October 26, 2005). [National Institute of Standards and Technology, 9/2005, pp. 82]