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01-17-2013, 04:32 PM   #35
ronray43
New User

Join Date: Apr 2009
Posts: 55

Quote:
 Originally Posted by J_R_B 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.