Attribution reporting is a method of analyzing the contribution of various marketing channels to a particular conversion event, such as a sale, lead, or download. It helps businesses to understand which marketing channels are most effective in driving conversions and to allocate their marketing budget accordingly.

In attribution reporting, the goal is to assign credit or attribution to the marketing channels that contributed to a particular conversion event. For example, if a customer made a purchase after clicking on a Facebook ad and later clicking on a Google search ad, attribution reporting would help to determine the relative contribution of each channel in driving the conversion.

There are different models of attribution reporting, each with its own set of rules for assigning credit to marketing channels. Some of the popular attribution models include:

1. First-touch attribution: In this model, credit is given to the first marketing touchpoint that the customer interacts with.
   
   
2. Last-touch attribution: In this model, credit is given to the last marketing touchpoint that the customer interacts with before making a conversion.
   
   
3. Linear attribution: In this model, credit is evenly distributed across all marketing touchpoints that contributed to a conversion.
   
   
4. Time decay attribution: In this model, more credit is given to marketing touchpoints that are closer in time to the conversion event.
   
   
5. Algorithmic attribution: In this model, an algorithm is used to assign credit to marketing touchpoints based on their relative contribution to the conversion event.
   

Overall, attribution reporting helps businesses to make data-driven decisions about their marketing strategy by providing insights into the effectiveness of different marketing channels.