Consider a recommender system which sends discount coupons for cakes to visitors on some website. There are 2 cases:
- good case: when a customer visits the website with no intent of buying a cake, but their behavior changed as a result of the seeing the recommendation. The website gained a new purchase.
- bad case: when a visitor already had the intention of buying a cake before seeing the recommendation. The website lost money by sending the discount.
How is this problem called? How is it quantified? What are the common solutions?