[pokergrader]

Potential Profit ranks your expected hand strength against a sliding scale of likely to unlikely hands your opponent is playing. It then uses this rank to count the money you put into the pot vs how much money your opponent put into the pot using this expected hand strength.

The only data points PP uses are your expected hand strength, the number of opponents, and the size of the pot. It doesn't look at what your opponents actually had or who ended up winning the pot.

If you have the nuts, you get 100% of the value of your money + your opponents money. If you have a good hand, (mid-set, non nut flush), you are probably getting a high amount, 80-90%. All the way down to a bad hand which perhaps is getting 0-30% of the money. By calculating this for every hand, PP is designed to determine how much money you will make on average for every hand you play, regardless of what actually happened. The FAQ on the site has some more information about it.

Since the blinds count against your PP (IE you have to be able to beat the blinds to have a positive PP), a slightly negative PP could just mean you weren't getting any hands and you were slowly being blinded away. Which over the course of 200 hands it is very possible for a good player to still average negative money due to the blinds. However if it is more than trivially negative (worse than -2 or -3 BB/100), then there are probably some sort of leaks in your game that you might want to look into.