Historians are uncovering gaps in the National Archives and analyzing data to find scores of classified documents that should have already been declassified and released to the public:

Krasner, who earned a PhD in mathematics at Columbia, is among a half dozen computer scientists, mathematicians, and statisticians now working with Connelly on a multimedia research project they call the Declassification Engine. For the past year, this team has been gathering up large numbers of federal documents and creating analytic tools to detect anomalies in the collections. Several of the tools are on the project’s website and available for anyone to use. The one Krasner is developing is intended to find evidentiary traces of important historical episodes — a diplomatic crisis, say, or preparations for a military strike — that scholars until now have failed to notice. The Columbia researchers suspect that by spotting something as subtle as an uptick in a diplomat’s telephone activity they may be able to reveal the existence of historical episodes that the US government has largely suppressed from the public record.

“If you can make out something happening in the shadows, then we can ask: does it seem curious that little information about this event is available in the public record?” says David Allen, a PhD candidate in history at Columbia who is working on the project.