This document discusses measuring the effectiveness of influencer marketing campaigns. It defines an effective campaign as one that is both profitable and scalable. To measure effectiveness, the document recommends calculating return on investment (ROI) by tracking marketing costs, revenues, and using proper attribution methods to connect influencer efforts to outcomes. The document outlines steps for attribution, including assigning unique landing pages to each influencer and using surveys to calculate a multiplier for indirect purchases. It also provides alternatives like engagement metrics and organic growth if direct purchases cannot be tracked. The key takeaway is to define clear metrics and set up proper tracking and attribution for each campaign.