Quote:
Originally Posted by sastoller
One thing I would like to hear opinions on is if eliminations match data should be use in OPR calculations.
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OPR was first proposed and published on CD by Scott Weingart in April 2006. Since then OPR has always been calculated using qualification match results only. Here are a number of possible reasons.
1) There were quite a few years where the scoring during qualification rounds and elimination/playoff rounds are different, some years more than others. Adjusting the scores for qualification rounds or elimination/playoff rounds in order to combine these different matches together to calculate OPR of both rounds is artificial and lead to potential unnecessary arguments how the adjustment should be made.
2) The motivation for teams in qualification rounds and elimination/playoff rounds are very different. The higher ranked teams want to rank as high as possible by winning a match and earning as many ranking points as possible that is used for tiebreak. Lower ranked teams want to showcase their strength and winning is not the highest priority except for their obligations to their alliance partners. In elimination rounds, the goal is to advance by winning and not necessary by scoring as many points as possible. In playoff rounds, the goal is to score high to advance and winning may not be the top priority.
3) Alliance partners in Qualification rounds are randomly selected. That is not the case for elimination/playoff rounds. In some games, with better partners, teams in elimination/playoff rounds are limited in number of points each of them can score which can hurt their OPR.
4) In the calculations of OPR, if we use elimination/playoff matches also, there may be some undesirable effect when some teams play more matches than others. More data points may not be better when the data represents something different due to what I explained above.
However I am all for teams who want to modify OPR to rank teams based on what they feel is more important. 2012 was the only year that I published a modified OPR. There was a general consensus on CD to give 5 points for each coop point. I made it so that teams can easily use a number different from 5 if they chose to.
Due to all the above reasons, I strongly oppose changing the fundamental way how OPR is calculated. If anyone wants to change it, make sure you call it something else so that the community is not confused with what you are publishing.