History & CultureMental model
Source criticism: four questions before you believe a source.
Historians test every source with fixed questions: Who wrote it? When, and how close to the event? For whom, and with what intent? What could the author actually have known? A battle report by the victor, written 30 years later for the court, isn't worthless, but you read it differently from a private letter written the same evening.
Useful: The four questions work just as well on news articles, product reviews and company reports.
Source: de.wikipedia.org