### Formula aggregation:

This feature allows Causal to easily calculate the appropriate roll-up value of formulas that generate percentages across categories . A good example of this is to think of gross margin between two different areas:- Profit Centre A - $100K in Net Sales, $90K in Costs - Gross margin is 10%
- Profit Centre B - $1M in Net sales, $500k in Costs - Gross margin is 50%

By default, Causal will display the Gross Margin variable (Net Sales-Revenue)/Net Sales as a “Sum” - so we would see 60% as our top-level Gross Margin. A common way around this is to use the “Average” category aggregation, which would display a 30% Gross Margin. This value is also incorrect, as Profit Centre B has much higher net-sales, and its impact to margin should be greater than Profit Centre A. Logically - the way to do this calculation appropriately would be to add the sales and costs of both profit centres, and then apply the calculation. This is what the “formula” category aggregation helps us achieve, giving us the correct value of 46.4%