One of our Advanced Reporting platform features, expressions, are used to define custom calculations and columns in reporting. We find expressions useful to pass in the proprietary data that you are not passing into the Facebook SDK or mobile measurement partner. This allows you to import in-app events or offline events and see the data in AdRules mapped to your Ad Set’s targeting.
To create an expression, click on Metrics
To create an expression, select your data from the two columns and the mathematical operation between the two.
You may add, subtract, multiply or divide between the two columns.
In column two, you may also add numbers in addition to the metrics. You may use this option if Facebook data is over or under reporting, and you want to compensate for this discrepancy.