Message Font: Serif | Sans-Serif
 
UnThreaded | Threaded | Whole Thread (17) | Ignore Thread Prev | Next
Author: woof321 Two stars, 250 posts Old School Fool CAPS All Star Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: of 8074  
Subject: Re: Guess What our Leaders Are Doing? :) Date: 2/1/2007 11:42 AM
Post New | Post Reply | Reply Later | Create Poll . Report this Post | Recommend it!
Recommendations: 1
Say the 20 pick guy after a year is up 15 pts on his correct picks and down 15 points on his incorrect ones. With his 75% accuracy this gives him a score of 150 ((15*15)-(5*15))
The 200 pick guy is also up 15 on correct picks and down 15 on incorrect ones. With his 60% accuracy he has a score of 600 ((120*15)-(80*15)).

I don't think normalizing is the way to go, so we need accuracy. Just fix the exploits.


Your example is the only case in which accuracy is a useful metric - when all winners and losers are exactly the same size. The problem is that players are encouraged to let their losers get much bigger than their winners, then accuracy no longer means anything. The simple solution is to weight picks by their size in the accuracy calculation (essentially remapping to a set where all the picks are equally sized). That's exactly what my "point efficiency" formula does.

Suppose I told you I had an absolutely fool-proof strategy that allows me win money in 72% of my casino visits? Impressed? Okay, how about one that wins over 92% of the time? How about winning 97% of the time? Suppose some professional poker player makes far more money/year than I do at gambling (even when I'm using my 97% method), but he only wins about 40% of the time. Well, I'm still much more "accurate," right? See why this metric is completely useless if we don't account for the size of the wins/losses?

Dave
Post New | Post Reply | Reply Later | Create Poll . Report this Post | Recommend it!
Print the post  
UnThreaded | Threaded | Whole Thread (17) | Ignore Thread Prev | Next

Announcements

Post of the Day:
Macro Economics

The Future, or What's Left of It
What was Your Dumbest Investment?
Share it with us -- and learn from others' stories of flubs.
When Life Gives You Lemons
We all have had hardships and made poor decisions. The important thing is how we respond and grow. Read the story of a Fool who started from nothing, and looks to gain everything.
Community Home
Speak Your Mind, Start Your Blog, Rate Your Stocks

Community Team Fools - who are those TMF's?
Contact Us
Contact Customer Service and other Fool departments here.
Work for Fools?
Winner of the Washingtonian great places to work, and "#1 Media Company to Work For" (BusinessInsider 2011)! Have access to all of TMF's online and email products for FREE, and be paid for your contributions to TMF! Click the link and start your Fool career.
Advertisement