Overview and Analysis of FIRST Stats

[wgardner]

Originally Posted by AGPapa

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.

Thanks! That clears things up a bit. And these are all still with Var(N)/Var(O)=2.5 like before? Can you post a link to Ed Law's spreadsheet? (Sorry, I'm really an FTC guy coming in late to the CD FRC forums.)

Compare your chart with the bottom left chart of this (from a few posts ago, and from a simulated 2014 casa tournament). The blue lines at the bottom of that chart are if the OPRs are known to within a standard deviation of 0.3 times the overall standard deviation of all of the OPRs, and the red/pink/yellow lines are if the OPRs are known to within 1.0 times the standard deviation of all of the OPRs. Your bottom chart looks like it could be somewhere between those two. (Also note that my chart is percent of the variance of the error in the match result prediction, whereas yours is the absolute (not percent), standard deviation (not variance) of the error in the match result prediction, so they're just a bit different that way. As the stdev is the square root of the variance, I would expect that the stdev plot to be flatter than the variance plot, as it seems to be.)

Could you compute the standard deviation of the error in your "OPR prediction" (i.e., compute the OPR from worlds minus the OPR from the previous regional tournaments, and take the standard deviation of the result)? And then compare that to the standard deviation of all of the OPRs from all of the teams at Worlds (i.e., just compute all of the OPRs from Worlds for all of the teams and compute the standard deviation of those numbers). It would be interesting to know the ratio of those two numbers and how it compares to the plots in my simulated chart where the ratios are 1 and 0.3 respectively.

And I guess while I'm asking: what was the standard deviation of the match scores themselves?