I would presume that getting a good result (3rd) in a Flat is Fast Advanced (650-1000) event would result in a bigger ZRS bump than getting 1st in a Range 2 (A) race.
I get that its possible to have a “higher quality” field in the lower category, but I really doubt that was the case. Top 3 in the latter race had scores in the 500s, while 1st & 2nd in the Advanced race had scores in the 800s.
I suppose in the end it doesn’t really matter because one can always race up in the higher category/range, but I was led to believe you could force your ZRS up quicker that way.
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I don’t think anyone outside of Zwift really knows enough about how Zwift has modified the OpenSkill defaults to understand how this works.
We do see big swings in numbers for races with small attendance for some reason which is not something that is baked into OpenSkill from what I understand. So that is just one example of something that is hard to explain in ZRS.
It is theorized (not sure if confirmed) that Zwift is using a (mu - [3*sigma]) value for ZRS rather than mu (where mu is your current “skill” in the program and sigma is a standard deviation that represents the uncertainty in your score).
If this is true, it means you can get an increase in ZRS score from both a lower uncertainty (you did what the system thought you would do so they are more certain of your skill and sigma will go down - in which case mu-[3sigma] gives you a higher ZRS), or by doing something better than your skill (you beat people who are higher ranked than yourself) in which case mu goes up so mu-[3sigma] also goes up.
Again, I don’t think it’s confirmed they use mu-[3*sigma], but if that is what they are doing it would account for a lot of the ‘why does half the group go up, half the group go down’, ‘why does it seem the skill of folks around me doesn’t matter’ etc… which should not be what happens in an OpenSkill model in general.
Would certainly be nice for someone from Zwift to clarify what should be expected, and maybe give a bit more details on how things are supposed to work.
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Thanks for the quality reply!
It isn’t working as intended.