As a critique of The Intercept’s story yesterday by Jeremy Scahill and Margot Williams on a catalogue of the U.S. government’s wide array of eavesdropping equipment, several people who identify themselves as national security reporters or security experts claimed that the documents Scahill and Williams published were from 2006. They pointed to a designation in the lower right-hand corner of some of the documents that reads: “DERIVED FROM: DATED: 01 May 2006.”

This claim is false, and is based on a lack of familiarity with basic characteristics of classified government documents. The classification marking they cite does not identify the date of document creation. It is, rather, the date on which the source information was classified or relevant classification guidelines were published. As a training booklet from the National Archives — titled “Marking Classified National Security Information” — makes clear, this portion of a classified document is referred to as the “classification authority block.” Officials who prepare classified documents are to “precisely identify the source document or the classification guide on the ‘Derived From’ line, including the agency and, where available, the office of origin, and the date of the source or guide” (emphasis added).

Note in the example that the document post-dates the classification block at the bottom of the page: The document itself is dated July 15, 2010, which is when it was created, but its classification block indicates June 27, 2010. That is because those dates refer to two completely different events. This is standard intelligence community practice. For instance, many of the documents in the Snowden archive that were created in (and are thus dated) 2012 or 2013 bear a classification authority block at the bottom of the document of 2007. One of the first Snowden-based articles in The Guardian — a June 2013 story on the NSA’s “Boundless Informant” program — explains this point in order to avoid confusion for readers unfamiliar with how to read classified documents: