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Discussion: AP maths

in: Rachel; Rachel > 2019-04-22

Apr 22, 2019 11:41 AM # 
Juffy:
Weirdly, you and Ceri have the same average speed, she lost less time in errors but came in 30s behind you. Maybe if we mention Ken's name three times, Ken the Magical AP Fairy will appear and explain how Ken's maths works. :)
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Apr 22, 2019 12:09 PM # 
Rachel:
Ha, ha. Hadn't noticed but agree that's a bit weird.
Apr 22, 2019 1:41 PM # 
O-ing:
Interesting you say you lost time on 2 with 1:22 but it doesn't show up as a mistake. But then if you look at W45 who were on the same course, Martina did that leg in 1:02, yep,so it was.
Apr 22, 2019 1:45 PM # 
O-ing:
I kind of know, because I had the same course as well, and I did 1:22 as well, and I know I made a mistake as well, because I headed to the wrong gully. But it doesn't show up as a mistake on my splits either.
Apr 22, 2019 2:30 PM # 
tRicky:
I had many more errors than the two that show up in my splits but it just depends on what others on your course did.

Interesting on the speed issue too. W21E from the long day has Belinda faster than Tash despite being a minute longer but only 20s more in errors.
Apr 23, 2019 1:57 AM # 
Rachel:
It was a pretty small mistake at number 2, maybe 10-20secs really, so didn't necessarily expect it to show up on splits.
Apr 23, 2019 2:44 AM # 
O-ing:
Well it was 32% over Martinas time for that leg, so I think it would have showed up on mine!
Apr 23, 2019 2:47 PM # 
ken:
Regarding maths, the first thing to know is that the speed value is not average speed, it is more like "cruising speed" or ideal speed. I forget exactly how it is calculated and it wasn't obvious to me when I took a quick look, but you can assume it is something like average speed (by leg score--relative to the top 3 splits) on your best half of the legs.

Any splits that are a bit slower on a relative basis won't be represented in either the mistake time or the cruising speed index, so that's what makes the difference in overall time.

Regarding the threshold for mistakes, AP is only comparing against those on the same course as uploaded, it won't compare against other common legs even if the whole course is the same. On #2, it looks like nobody was much faster in W40, and in M60 O-ing is probably just under the arbitrary criteria for a mistake (not comparing against Martina), which you can see by your low leg score.

So in summary, it's all a mystery to me too :)
Apr 24, 2019 1:13 AM # 
blairtrewin:
I think the strangest experience I had with AP maths was when I ran a hilly 10k and the climb-adjusted kilometre rate was faster than my split for any individual kilometre, even the downhill ones.
Apr 24, 2019 2:02 AM # 
tRicky:
AP must have adjusted your rate to suit the climate change agenda.
Apr 24, 2019 3:10 AM # 
O-ing:
That makes sense if you were pushing up the hills and relaxing downhill.
Apr 24, 2019 3:13 AM # 
O-ing:
Ps. Thanks Ken! Such a great piece of software! I do think it would work even better if people would load splits combined by course rather than split into classes.
Apr 24, 2019 3:23 AM # 
tRicky:
I think it's something to do with the way it was set up in the event software since I only seem to encounter this issue with major foot events. As I mentioned to you previously, uploading the NSW MTBO champs combined classes on different courses but this one didn't. That was also MeOS whereas this was OE.
Apr 24, 2019 7:40 AM # 
Juffy:
Yup - entirely driven by the way it's set up for the event. Actually it's always set up by class in OE, just that for minor events each course has one class and that's conveniently named the same so no one notices except the poor unfortunate bugger who has to set it up.

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