"Statistics are important in ProTrade, too, but the system tries to provide more context by analyzing the situation in which a play occurs. As an example, a 3-yard run on fourth-and-2 would be worth more than a 3-yard run in a third-and-20 situation."
How do they "provide more context" by giving a bonus for first downs? Is the play worth even more if it happens in the 4th quarter or if the score is close. It seems like there are too many unknowns and opinions of what is more/less important to attach a value for each event.