In marketing, attribution is the art and science of determining what ad campaigns drive conversions. Conversions can be a sale measured with a transaction value measured in a currency. Other “conversion events” can be a signup or registration for a website, and credit for such a conversion can be assigned to marketing touchpoints in the same way.
Before someone purchases a product or service, they can be exposed to numerous marketing “touch points”. These touchpoints cover a wide range of interactions, from seeing a YouTube video to conducting online price comparisons and searching Google. Attribution is assigning credit or allocating dollars from a sale to the marketing touchpoints that a customer was exposed to prior to their conversion. In proper attribution modeling, that credit is assigned proportionally to each touchpoint according to its influence on the customer’s purchase or conversion decision.
Note that all attribution models fall short of the goal of understanding each touchpoint. The goal of attribution modeling is not to be perfectly right, but to be a little less wrong every time. For example, the “Last Click” model assigns all credit to the last touchpoint and ignore all earlier activity. The First-Click model does the opposite, giving all credit to the first touchpoint and ignoring all others. Despite the inaccuracies in these models, they are still used today by many advertisers to determine the value of touchpoint, one reason being that Last-Click is often the default setting.
Its important to know that every attribution is the result of consistently applying a set of rules, such as “when we observe x, we do y”. Google AdWords says that “An attribution model is the rule, or set of rules, that determines how credit for sales and conversions is assigned to touchpoints in conversion paths.” For example, the Last Interaction model in Google Analytics assigns 100% credit to the final touchpoints (i.e., clicks) that immediately precede sales or conversions. In contrast, the First Interaction model assigns 100% credit to touchpoints that initiate conversion paths.
Source: Google AdWords