Analysts do not achieve objective analysis by avoiding preconceptions; that would be ignorance or self-delusion. Objectivity is achieved by making basic assumptions and reasoning as explicit as possible so that they can be challenged by others and analysts can, themselves, examine their validity.
Psychology of Intelligence Analysis by Richards J. Heuer, Jr. page 10
Good quote. People should write down all their assumptions when doing data analysis. It’s a very contingent game.