Definition of implied rating
Implied odds are the money you think you will make on the upcoming street if you hit your draw. They are difficult to calculate since they estimate how much money our opponent will be willing to pay on the turn or river if you hit your draw. However, they must be taken into account. When calculating the pot odds and arriving at a close (or even slightly losing) decision, a call can be justified by talking about the implied odds.
An example of an implicit rating
You are on the turn with three of a kind (99 on 9-5-4-J). You are convinced that your opponent has a flush. But he's a stubborn sort and you know he won't fold the flush no matter what the river is and no matter what your bet or raise on the river is. He bets on the turn for half the pot. Normally, you would have to tell yourself that you are going to hit your full hand 1 in 5 times on the river and that you can't mathematically justify a call on the turn of a 50% pot bet. But if we know that when we hit our full hand, our opponent will be able to pay us big, we would say that we have the implied odds to call the bet. Generally, the less experienced our opponent is, the better our implied odds.