In All Inventory, Potential Traffic is an estimation of how much traffic you could have if you were to optimize this page-topic pair. To do this we:
- First determine potential rank based on the current rank and Personalized Difficulty.
- Then we calculate the possible traffic taking into consideration potential rank and the topic’s monthly search volume.
In Topics Inventory, the calculation is based on the highest ranking page for that topic — we account for the possibility that multiple pages rank for the same topic.
In Pages Inventory you have one page ranking for multiple topics. So we add up the Potential Traffic for each ranking topic to arrive at the total. It’s the potential traffic you could gain if you optimized the page for each topic or created new pages on each topic. That’s really a better way to look at it since you wouldn’t optimize one page for so many topics — you would create new pages.
Note that potential traffic takes into account SERP features and their impact.