The stars are created using a StatFox proprietary calculation based on may factors like the record of the system and the length of time the record represents.
Some people have created their own systems by counting stars, or looking for the side with higher amount of 5 stars, but to track specifically we just keep track of the record of each situation or trend.
The record is kept for each situation or trend and is displayed along with it.
There are usually several situations and/or trends for each side in every game so I am not sure how you would track them for who one unless you add them up for each side and take the side with more stars.
In my opinion, just adding up the stars on each side is not a good way to use the FoxSheets though. I think it is better to evaluate each one and decide if the combination of several of them, along with the game simulator helps you to make a choice for a specific side.
Speaking of the simulator, if you are only talking about just the green star for the Edge on the game simulator, then that is a good indicator and should be given as much weight in your handicapping as the total stars for the situations or trends. Again that is just my opinion though.
Maybe someone else will chime in with how they use the green stars.