How we cite our quotes:
The present narrator has three kinds of data: first, what he saw himself; secondly, the accounts of other eyewitnesses (thanks to the part he played, he was able to learn their personal impressions from all those figuring into this chronicle,); and lastly, documents that subsequently came into his hands. He proposes to draw on these records whenever this seems desirable, and to employ them as he thinks best. (1.1.9)
The narrator uses terms like "data" to give the illusion of factuality and objectivity. This is ironic, since the narrative quickly proves how useless language is with its flexible definitions.
When leaving his surgery on the morning of April 16, Dr. Bernard Rieux felt something soft under his foot. It was a dead rat lying in the middle of the landing. On the spur of the moment, he kicked it to one side and, without giving it a further thought, continued on his way downstairs. Only when he was stepping out into the street did it occur to him that a dead rat had no business to be on his landing, and he turned back to ask the concierge of the building to see to its removal. (1.2.1)
The use of dates is yet another tool to give the narrative credibility and the illusion of journalistic integrity.
Personally, he had thought the presence of the dead rat rather odd, no more than that; the concierge, however, was genuinely outraged. On one point, he was categorical: "There weren’t no rats here." In vain, the doctor assured him that there was a rat, presumably dead, on the second floor landing; M. Michel’s conviction wasn’t to be shaken. (1.2.1)
It seems the truth is always up for debate: false convictions are hard to shake.