Also known as the last-click model, this is the default model set by Google Analytics whenever a conversion is configured. This model allows you to see the last channel from which the user converted.
Example: A user clicks on a Facebook ad and completes the conversion. This model would assign the conversion to the Social channel.
However, it's important to keep in mind that this isn't always the best approach for analyzing conversion paths. For example, imagine the same user saw the latest mailing database ad on social media, but instead of clicking on it, they decided to visit the website directly from the address bar. This model would attribute the sale to the Direct channel rather than the Social channel. Therefore, this attribution model would be inaccurate when analyzing the performance of social media campaigns.
First interaction attribution model
This model works in the complete opposite way to the previous one. That is, it will award 100% of the value to the first channel the user interacted with.
Example: A user finds your website by clicking on one of your Facebook ads. A week later, they return to your site by searching for the URL directly. Finally, two days later, they decide they want to convert, search for, and click on a Google Ad. This model would attribute the conversion to the Social channel.