The Washington Post’s analysis is based on an examination of those emails from Hillary Clinton’s 52,000 pages of publicly released correspondence that the State Department has said contained classified information. The emails, spanning Clinton’s term as secretary of state from 2009-2013, have been released under court order, with the final batch disclosed last week.

Many of the emails came as part of lengthy communication chains, making it difficult to decipher the author of each email message.

The Post sought to separate the chains into individual emails and then identify the author of each email that contained redactions because of the government’s classification.

These emails have been marked by the State Department with the code “B1,” corresponding to an exemption under the Freedom of Information Act guidelines reserved for classified material. The Post did not examine emails redacted for other reasons, including because they involved discussions of internal department deliberations or personal private information.

The Post examined every page by hand. At times, some interpretation and judgement were required in the count.

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In all, The Post found that the State Department redacted all or portions of 1,789 individual emails because of the presence of classified information. Of those emails, 104 were authored by Clinton and 1,685 were written by 298 other people.

This is a different tally than one released by the State Department last week, which found that 2,093 chains of Clinton’s correspondence contained at least one classified redaction.

The discrepancy reflects the different approaches used by The Post and the State Department.

State measured the number of times an email chain containing a classified redaction traversed Clinton’s server. The Post, however, examined each chain to determine the author of every email with a classified redaction.

The result was that, in some cases, the State Department’s tally for an email chain was higher than The Post’s. In others, The Post’s count was higher.

For instance, if Clinton and an aide exchanged four unclassified emails about a note from a diplomat that has now been classified — each time including the diplomat’s email — the State Department’s tally counted the exchange four times. The Post counted it once.

On the other hand, if an aide forwarded an email chain to Clinton one time that included 12 notes with classified redactions written by 12 different employees, the State Department’s tally counted the exchange just once. Under the Post analysis, all 12 individual classified emails were counted and their authors tallied.

Subject lines created another analytical challenge.

In some cases, the subject line was the only information in an email that was redacted. Once a classified subject line was introduced to an email chain by one author, it was generally used by all subsequent correspondents in a chain. The Post considered the author of every email with the subject line as the author of a classified note, since any author could have changed the subject line.