Last-click attribution is a legacy attribution model that assigns 100% of the credit for a conversion to the last touchpoint or interaction a user has with an ad before the conversion point. It is straightforward and easy to implement, often used in digital marketing to evaluate the effectiveness of campaigns, while containing several limitations and constraints:
 

• Ignores earlier interactions: last-click attribution ignores all prior touch-points that may have played a significant role in influencing the user's decision.
• Poor decision making: This model often leads to misattribution and misallocation of marketing budgets by overvaluing certain channels (i.e. search) and undervaluing others (i.e. social media).
• Limited insights: It offers limited insights for optimizing the entire customer journey, as it does not account for the contribution of various touch-points in the conversion process.
• Bias towards performance-focused channels: Channels that optimize optimize towards winning credit may receive disproportionate budgets, leading to a flaw in a vicious cycle in budget allocations.