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Why is P/BB so variable?

Posted: Mon Jun 10, 2019 8:04 pm
by DavidB256
Looking at the stats for the 2019 PACE NSC, I noticed that the P/BB (points per bounceback) statistic correlates very poorly with both overall placement and P/B (points per bonus). I understand that P/BB is a function of both the skill of the team and the skill of the teams they play against (playing against better teams would decrease your P/BB because they are more likely to get all of the easier bonus parts), but I don't understand how that can lead to some of the existing results. For example, the Championship bracket had a range of 4.49 P/BB, the 9-16 bracket had a range of 4.74 P/BB, and my team, which got 59th, had more P/BB than DCC A.

Does anyone know why this is?

Re: Why is P/BB so variable?

Posted: Mon Jun 10, 2019 10:59 pm
by Santa Claus
DavidB256 wrote:
Mon Jun 10, 2019 8:04 pm
I understand that P/BB is a function of both the skill of the team and the skill of the teams they play against (playing against better teams would decrease your P/BB because they are more likely to get all of the easier bonus parts)

Re: Why is P/BB so variable?

Posted: Mon Jun 10, 2019 11:13 pm
by Cody
As noted, bouncebacks are extremely opponent-dependent and won't tend to average out over a large sample size like other statistics such as PPG because there isn't a large sample size as compared to the variability in getting the bounceback correct.

Another consideration is that (iirc) SQBS reports bouncebacks as a function of fractions of a bonus. You have to divide P/BB by 3 to get points per bounceback. This greatly reduces the range and the other usual statistics (std dev).