What is the difference between an
Additive, Semi-Additive, and Non-Additive Fact? Can you give examples from your project?
Answer:
- Additive Facts: These can be summed up across all dimensions. In our project, Claim_Payout_Amount was fully additive—we could sum it up by agent, branch, month, or policy type.
- Semi-Additive Facts: These can be summed up across some dimensions, but not across time. In our project, Policy_Account_Balance or Outstanding_Reserve_Amount was semi-additive. You can add them up across different branches for a specific day, but you cannot add a month-end balance across all days of the year.
- Non-Additive Facts: These cannot be summed up at all. Ratios or percentages fall here, such as a Loss_Ratio. Instead of adding ratios together, the warehouse calculates them dynamically by dividing total claims by total premiums
