One possible problem is the information's origin. For social information, people may exaggerate or misrepresent facts, intentionally or subconsciously. New data gathering techniques can filter out important data.
Intangible ideas, like power, are difficult to capture in a measurement or single story. New techniques in natural sciences to measure objects could produce different measurements than older ways. This could over or underestimate the results.
Reporting is difficult in both sciences to remain neutral and not over or understate the results. For most projects, it is impossible to capture all variables. The report must be clear what was and was not included. Also, readers may have different interpretations of results based on their research or interests in the subject.