The last-click rule is a marketing attribution model that gives credit for a conversion or sale to the last touchpoint a customer interacted with before making a purchase. This means that the final action a customer takes, such as clicking on an ad or link, is considered the most influential in their decision to buy. While this rule may be simple, it can be a valuable tool for businesses to understand which marketing efforts are most effective in driving conversions and optimizing their advertising strategies. However, critics argue that the last-click rule oversimplifies the customer journey and fails to give credit to other touchpoints that may have played a role in the conversion.