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Old 01-17-2013, 04:32 PM   #35
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Join Date: Apr 2009
Posts: 55

Originally Posted by J_R_B View Post
This is a myth due to one misinterpreted statement by the USTA that is now perpetuated on here endlessly. The fact is that the expected outcome of a match between two players 0.5 apart is not 6-0 6-0. What the statement said is that a 6-0 6-0 match is not unexpected for players with a 0.5 difference. But matches between any two players will have a whole distribution of possible outcomes. If the expected outcome is 6-0 6-0 only 5% of the time (or 1 on 20), then it's still not unexpected, and since there are thousands of matches in the system between players with this ratings difference, seeing some 6-0 6-0 outcomes is normal and expected. They were writing in the context of people who see a 6-0 6-0 outcome and start jumping up and down that that person is automatically misrated or worse, sandbagging. The fact is that the expected outcome (in terms of a mathematical expected value or average) of a match between two players one level apart is probably about 6-2 6-2 or something like that with 6-0 6-0 having enough positive probability that it's not unexpected or unusual to see some in the real results.

I play 4.0. I'm probably near the top of the 4.0 range (I was 14-2 last year but wasn't bumped). I won a match against a 4.0 rated player 6-0 6-0. It was a kid who wasn't bad, but I just happened to get all the games. I also won a match 6-0 6-2 against a 3.5 playing up. The 4.0 kid was a lot better than this guy, but in the course of this match, I happened to lose a couple games. The 6-0 6-0 kid also lost 6-0 6-3 to another college kid who was bumped at the end of the year who can kick my *** all over the court. If we all played a hundred matches, I would probably win 2 or 3 by double bagel against the kid and the other kid would probably win 15-20 by double bagel. That's not how the actual record is, though, and seeing my 6-0 6-0 win in the record is not a sure sign that I am under rated or that my dynamic rating is or should be lower than the other kid who got bumped and who can kick my ***.

You have to be careful about how you interpret statements and expectations keeping in mind that individual match results are a random draw from a distribution and not a fixed measurement of the difference in ratings.
From the USTA website, "Are all players in a given NTRP level equal in ability?
No: The NTRP system identifies general levels of ability, but an individual will be rated within those levels at 50 different hundredths of a point. For example, a 3.5 player can fall anywhere between a 3.01 and a 3.50. That is the reason many people feel they are playing sandbaggers they are closer to the bottom of that range while their opponents are closer to the top of the range.

A typical match result for a player, for example, with a 3.01 rating versus a 3.49 player, both of whom are 3.5s, would be 6-0, 6-0 in favor of the higher rated player.
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