Abstract: A method of quantifying the effectiveness of delivery of digital media content comprises identifying a group of instances of delivery of digital media content, calculating a plurality of metrics for the group, each metric indicative of a different aspect of effective delivery of the digital media content, and combining the calculated metrics into a single indicator of the effectiveness of the delivery of digital media content for the group. The group of instances can represent the delivery of digital media content by a particular supplier or a particular service of a particular supplier of digital media distribution services over a period of time. The metrics can be indicative of the proportion of the instances that were visible or audible to a viewer of the digital media content.