Delaware Valley Orienteering Association

Topic created by johncampbell on Mon Feb 24, 2014 at 10:46 pm

johncampbell
Num Posts: 88
Primary Club: DVOA
Fav map: Batsto
First O: 1969

Looking at results yesterday and the ranking points has me intrigued by the ranking calculation methodology. On the green course my stats were Pace 8.46min/km, PCR 3739, CGV 4392 - ranking points 69.2 Petr Hartman ran the red course and his stats were pace 10.21 min/km, PCR 5094, CGV 4693, ranking points 76.13. While I understand that the red course is more difficult, I am interested to know where does the per/km come into play? How is the PCR and CGV determined? From a course planning perspective the only difference between green and red is the distance. I am interested if someone can tell me what per/km time I would have to run to have got the same points as Petr. Not that my ranking really matters but interested to understand the methodology.

Reply by ErikEddy on Tue Feb 25, 2014 at 10:27 am

ErikEddy
Num Posts: 410
Primary Club: DVOA
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First O: 1998

http://www.dvoa.org/rank/calcrank2013.php

I don't fully understand either.  My understanding is that the rankings become "more accurate" as the year progresses.  I believe your score at each event will actually change throughout the year since the "field strength" is based off of everyone elses rankings.

My question is... do the rankings totally reset?  Or are they based off of previous year's results (to determine "field strength)?

Reply by Vadim on Tue Feb 25, 2014 at 12:11 pm

Vadim
Num Posts: 221
Primary Club: DVOA
Fav map: Stuckey Pond
First O: 1983

Prior to 2013, rankings started fresh each year and we needed at least 4 races to run calculations. Since last year your rankings score is available and can be used for current calculations. But if you did not run last year or are a new to orienteering, the system will use score 50 as the initial value and readjust during calculations and over the year.

Reply by Vadim on Tue Feb 25, 2014 at 12:13 pm

Vadim
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As for the PCR and CGV numbers, I'll let you know later have to refresh my memory )))

Reply by Steve on Tue Feb 25, 2014 at 6:40 pm

Steve
Num Posts: 402
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First O: 1993

rankings are comparative. Let us say that Tom beat Bill on red, while Joe beat Harry on Green. Since Joe and Tom were doing different things, we can not compare. Next week, Tom decides to run green, and beats Harry but not Joe. We can now say that Joe is the best, Tom is next and Harry and Bill are some where near the same, based on how much Tom beat them on the different weeks. As Erik and Vadim said above, the more runs we have, the better this system works.

The system needs to adjust everyones ranking several times to arrive at a ranking also. As Vadim said, we are assigned a ranking of 50 out of 100. As the system runs the calculation, Some people will get bumped up, while others get bumped down. Since we were comparing different courses, we then have to run the program again, with the new numbers. Again, some will rise, and some will fall, but not by as much. When the computer decides that the change per run is negligable, it then posts the results, until you go and run another event, adding data,and demanding a new ranking.

The course gnarly value is done the same way, only the courses are evaluated using the runners as the constant. The Personal course ranking is again done the same, but this time you are the constant.

Hope I helped.

Reply by Vadim on Tue Feb 25, 2014 at 9:34 pm

Vadim
Num Posts: 221
Primary Club: DVOA
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First O: 1983

Thank you Steve for explanation. The magic numbers are 100 iterations until deviation is less than 0.001. The more data we have, the longer it takes to calculate, etc.

Reply by hughmac4 on Wed Feb 26, 2014 at 2:30 pm

hughmac4
Num Posts: 182
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Hmm, I don't see any scores at all. What am I missing?

Reply by j-man on Wed Feb 26, 2014 at 7:12 pm

j-man
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I think the scores are the carry over, year-end scores for 2013. They don't show up at the individual race(s), but rather in the total row.

Reply by hughmac4 on Thu Feb 27, 2014 at 2:11 pm

hughmac4
Num Posts: 182
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Hmm, ah, I see, in the individual records. And it's not actually showing scores yet (other than in the totals), so maybe something administrative needs to happen to move to 2014, and Vadim will take care of it when he's back from his travels? and has the time.

Reply by hughmac4 on Thu Feb 27, 2014 at 2:27 pm

hughmac4
Num Posts: 182
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Or if I read Vadim's post more carefully, I would have realized that there must be 4 events before the scores populate. I think! :)

Reply by ErikEddy on Thu Feb 27, 2014 at 5:30 pm

ErikEddy
Num Posts: 410
Primary Club: DVOA
Fav map: Mount Penn Antietam
First O: 1998

I see what Clem is saying.  There are no ranking values for this year yet.  John's 2013 ranking value was 69.2 and Petr's was 76.13.  The "Total Score" values are not related to Batsto. 

Reply by johncampbell on Thu Feb 27, 2014 at 10:46 pm

johncampbell
Num Posts: 88
Primary Club: DVOA
Fav map: Batsto
First O: 1969

Thanks everyone for the responses. I have a better understanding of the system being continuous and the part that matters is the year end. Bottom line, shed some lbs, get more in shape and get my butt out to more DVOA events!

Reply by furlong47 on Thu Feb 27, 2014 at 10:55 pm

furlong47
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We had a loooooooong winter meeting the one year where Kent explained how the rankings system worked, complete with a giant wall flow chart with pieces of paper moving around. We probably should have made a video of that 

Reply by anniemac on Fri Feb 28, 2014 at 1:10 pm

anniemac
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Correct me if I'm wrong but we are not doing Kent's way now, we have changed things slightly since then.

Reply by hughmac4 on Fri Feb 28, 2014 at 5:05 pm

hughmac4
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Erik & Clem:

Reply by furlong47 on Sat Mar 1, 2014 at 11:56 pm

furlong47
Num Posts: 379
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There were some changes a year or two ago, but the general structure is still similar.

Reply by Vadim on Sun Mar 2, 2014 at 9:51 pm

Vadim
Num Posts: 221
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First O: 1983

The world is not perfect and I'm not perfect too ))) The Total Score at the bottom of individual results is a glitch with few more glitches to add. It was Okay when we had Rankings data generated for the year, but it does not work correctly when there is no data yet. Oh, well, time is not on my side anymore, but I'll make a note and add this to the list of to do things.

In general calculations did not change much, we just made Rankings fully integrated into web site without processing on a side.

Reply by Len on Mon Mar 3, 2014 at 8:12 am

Len
Num Posts: 125
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I didnt mind the 'total' score showing a value. but I assumed it was my total from last year.
You could fix this easily by adding an asterisk stating 'The Total score will show last year's value until 4 events have been run in the current year' :)