[Bongle]

You could probably do a reverse-OPR as well. Rather than basing the OPR matrix on the sum of your alliance's scores, do another run that uses your opponent's score. That would give you the average amount that your team contributed to your opponent's score. Subtract reverse-OPR from forward-OPR, and that could get you a mathematical estimation of your +/- score without having to sit in the stands for 3 days at every regional.

What is OPR? It's a lot like simply taking your team's average score and dividing by 3, but a bit more complex and accurate. Do a search for it, there's a couple decent explanations. It is good because it can ferret out teams that just got carried along by good partners and didn't actually contribute to their high scores (something that a simple average cannot detect).