Imagine you are shopping for the latest trendy tech gadget at your favorite department store in a shopping mall. When you go to pay you hand your credit card to the cashier, and then the cashier tells you that your card has been declined, or even cancelled. This is a suspicion of fraud, because, for example, you have never made a purchase of more than $1,500 USD, so the transaction raises suspicions in the bank and the bank rejects the transaction and even blocks your credit card. 

It's a situation that, in theory, saves millions of dollars, and headaches, for your customers. However, when this system is not successful, it creates a bad experience with the consumer, making them feel embarrassed and frustrated, as they are unlikely to complete the purchase successfully. 

Banks and credit card providers must ensure that their systems are accurate, and that fraud detection is correct. That is the purpose of this competition, to improve those credit card fraud detection systems.