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Unread 16-03-2014, 21:58
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Re: Week3 cumulative Twitter stats & OPRs

Quote:
Originally Posted by dodar View Post
Then this truly isnt the correct OPR calculations
I can assure you that the algorithm I use to compute the L2 norm of the simple linear combination of team scores (what we're calling OPR) is correct.

But that leaves two questions:

1) What is the "correct" data to use, and

2) Is the L2 norm of a linear combination of team scores the "correct" algorithm to get the most meaningful and useful metric?

Question 2 has been discussed in various threads here on CD in the past. I won't beat that horse here.

Question 1 is especially problematic this year because of the high value and erratic enforcement of fouls (I am not blaming the refs: this is a difficult game to ref and score). To get a truer measure of performance arguably requires that the foul points be removed from the score before computing the OPR. The problem is, you can't do this with the official data. You need to use the Twitter data to remove the foul points.

Ed Law maintains a spreadsheet in which he makes every effort to "repair" the Twitter data whenever possible and deciding when and when not to integrate it with the official FIRST Match Results and Team Standings data. It's apparently a labor of love for Ed and he spends many hours getting it right, for which we are in his debt. If I tried to do that, I'd probably introduce more errors than I corrected.

So if you're looking for the "official" OPR, rather than the "correct" OPR, I would say that Ed Law's spreadsheet is the de facto standard.

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