Sources of information for casualty recorders are sometimes the evidence (narratives or documentation) that people or organisations produce.
Where evidence is being considered, sources can range from a book or official publication, through a news item (printed, web, or broadcast), the verbal testimony of an interviewee, to a photograph, death certificate, or piece of forensic evidence. When dealing with pieces of evidence as sources, casualty recorders are taking into account such factors as accuracy, detail, and level of corroboration, as well as the motivations and reputation of the organisation or individual that produced the document.
THE RANGE OF SOURCES IN CASUALTY RECORDING, p. 4