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Median vs. mean consensus grades
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Jun 26, 2012
Consensus grades on the site are currently calculated using the mean opinion. Switching to the median opinion would make the estimate more robust to outliers, and would prevent this sort of nonsense:

mountainproject.com/v/debbie-d...

(Administrator decides he doesn't like a 5.11a climb so he gives it a 5.0 rating and screws up the consensus grade.)
MikeJ
Joined Aug 4, 2011
0 points
Site Landlord
Jun 26, 2012
I deleted the bogus ratings, and the route comments related to them. Nick Wilder
From The Bubble
Joined Jan 1, 2005
1,461 points
Jun 26, 2012
If the sample size is large enough and its normally distributed then the mean and median should be the same. With that said, I'm not sure what the sample size is... agd
Joined Mar 31, 2010
0 points
Jun 26, 2012
alexdavis wrote:
If the sample size is large enough and its normally distributed then the mean and median should be the same. With that said, I'm not sure what the sample size is...

beat me to it.
except there is nothing normal about the distribution on MP!
Darren Mabe
From Flagstaff, AZ
Joined Dec 12, 2002
2,810 points
Administrator
Jun 26, 2012
i agree that the median is the way to go. slim
Joined Dec 1, 2004
885 points
Jun 26, 2012
Young Gun wrote:
Switching to the median opinion would make the estimate more robust to outliers, and would prevent this sort of nonsense: mountainproject.com/v/debbie-d... (Administrator decides he doesn't like a 5.11a climb so he gives it a 5.0 rating and screws up the consensus grade.)


agreed.
agd
Joined Mar 31, 2010
0 points


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