Overview and Analysis of FIRST Stats

[AGPapa]

Originally Posted by wgardner

Thanks AGPapa! As always, I have a few questions:

Can you elaborate on exactly what you mean by Oavg prior and World OPR prior? Does Oavg prior mean that you're setting them all to the same average a priori guess? Does World OPR prior mean that you're setting the a priori guesses to their final OPRs (as if you knew ahead of time what the OPRs actually were)?

I might expect that using the actual Worlds OPRs as priors would be uniformly good, as you're telling the algorithm ahead of time what the final guess would be (if I'm understanding you correctly, which I might not be). But I'm surprised that just setting the priors to be the overall average gives such uniform results.

Since your sim is probably easy to modify now (?), could you start it all off at 10 matches instead of 50?

Also, it doesn't surprise me that things get a little noisy at the very end because at that point you're only averaging the few matches left. They could just happen to be easy to predict or hard to predict and now there's only a few of them, so it seems entirely reasonable that they might move a bit from the trendline.

Ah, sorry for the confusion! "World OPR" refers to the OPR prior to the Championship event. It combines all regionals into one big "A" and "b" matrices and solves it. I just took that number from Ed Law's spreadsheet. It doesn't take any data from matches that haven't been played yet.

Oavg is just setting the priors to the average score of matches in the training set divided by 3.

I've attached the chart going back to match 10.