Every time a visitor is shown or clicking one of the products in the recommendation block, the event is tracked by engage. All the events are then on frequent basis processed and aggregated into statistics showing the performance of the recommendations. 

The "Direct Attributable Revenue" is calculated based on the criteria that a visitor/customers has clicked one or multiple recommendations and have within the time period of 7 days placed an order for the clicked item. The value the item is used for the calculation