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IBDvalueinvestin (98.35)

How they heck am I losing to vitrified in the Champion of the world contest???



May 19, 2009 – Comments (5)

1 vitrified 139.70 +95.91 76.00% 2 IBDvalueinvestin 348.25 +206.77 75.38% I am up by 200 points over him and down less than 1% on accuracy so how could I be losing?? Another rigged contest?

5 Comments – Post Your Own

#1) On May 19, 2009 at 2:41 PM, vitrified (93.76) wrote:

I bribed the Fool.  Ha, just kidding--I have no idea; I saw it listed that way for a moment, as well, though I assume it will sort itself out--you are clearly well ahead.

I sometimes notice that the ranking is temporarily thrown off in regular CAPS (not what it should be) when I enter a bunch of new picks, though I have no idea why.

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#2) On May 19, 2009 at 2:44 PM, portefeuille (98.87) wrote:

That might not be a bug but a feature. This "accuracy" effect can be really big!

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#3) On May 19, 2009 at 2:57 PM, IBDvalueinvestin (98.35) wrote:

the accuracy is suppose to be only 1/3 of weight while points count for 2/3 so I should be ahead all the time even if I have the worst accuracy??

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#4) On May 19, 2009 at 4:16 PM, portefeuille (98.87) wrote:

Have a look here

How is my rating calculated?

Here's how it all works. A member's rating reflects how often a member makes correct predictions (accuracy) and the percentage return of these picks (score). To compute member ratings we first give each member a percentile rank on score and a separate rank on accuracy.

Let's assume CAPS has only five members. First, we sort these members based on score and give them percentile ranks.

(table 1)

Then, we do the same with accuracy with one major tweak. Members are ranked on accuracy based on the PROBABILITY of achieving that accuracy and not the actual accuracy. For example, a member who makes 99 out of 100 correct predictions will be ranked ahead of a member who makes 7 out of 7 correct because it is much more difficult to be correct 99 times out of 100.

(table 2) 

The formula we use is

Raw rating = (2/3 * score rank) + (1/3 * accuracy rank).

(table 3) 

Finally, we sort these members and give them ratings! Note that member ratings are always percentiles, ranging from 100 (highest) to 1 (lowest).

(table 4)





You should have a look at table 2 and make sure you understand the formula

Raw rating = (2/3 * score rank) + (1/3 * accuracy rank) .

(the important word in "rank"!)

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#5) On May 19, 2009 at 4:44 PM, vitrified (93.76) wrote:

Thanks for the explanation, portefeuille.  With the current rankings, below, I was thinking that I couldn't possibly be ahead of Tyrone85 (he has both a higher score and higher accuracy), though he hasn't yet added more picks; so the "probability" tweak on the accuracy rating may explain the difference (I dumped in a lot of picks last night). 

1IBDvalueinvestin 317.51 +176.03 71.21%

2vitrified 122.33 +78.54 80.00%

3Tyrone85 129.53 +46.25 100.00%  

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