Waterboarding might be an excruciating procedure with deep roots in the history of torture, but for the C.I.A.’s Office of Medical Services, recordkeeping for each session of near-drowning was critical. “In order to best inform future medical judgments and recommendations, it is important that every application of the waterboard be thoroughly documented,” said medical guidelines prepared for the interrogators in December 2004.

The required records, the medical supervisors said, included “how long each application (and the entire procedure) lasted, how much water was used in the process (realizing that much splashes off), how exactly the water was applied, if a seal was achieved, if the naso- or oropharynx was filled, what sort of volume was expelled, how long was the break between applications, and how the subject looked between each treatment.”

The New York Times has an article detailing how carefully the CIA doled out its torture (with guidance from the White House, of course).