If you have data that's so 'dirty' that you can't decide on the filtering rules in advance (or based on only historic data), then what you have is garbage, not data. Therefore, we could call the art of shaping this into meaningful stories garbage science.

Tell me in a comment you have never worked with business data in your life.

Business data is full of minor inconsistencies which are not obvious until you sit in front of it. Products are sold by different units. Reporting ranges and aggregates are slightly different. Subsidiaries use categories which are close but not exactly identical.

There is generally plenty of massaging to do before you can get the information you need.