Why this game exists. Week 5 is dataset preparation and structuring, and the fastest way to learn it is to be handed something broken under a clock. Every round here is a real fault that shows up in an asset register: a key that is not unique, a date that is three different formats, a number that is secretly text. The wrong answers are not silly. They are the things people actually do, which is why they are worth getting wrong once here instead of once in production.