Originally Posted by jmnk
how is it flawed? What is so hard to understand that beating players that are no better than you will not make you move up?
If your dynamic rating is 3.89 (so you are 4.0 player) and you beat a player with dynamic rating of 3.52 (so he is also 4.0) by a score of 6:4 7:6 - how is that supposed to mean you should move up? By NTPR formula, which is based on old and proven ELO rating designed originally for chess (and now used very widely in competition where you can't possibly play --all-- of the opponents: tennis, soccer, on-line games, etc), the expected result is likely around 6:2, 6:2 - so you did worse than expected, which means your ranking went down despite the win.
Now have it happened 15 times over the course of the season and your dynamic ranking (and therefore NTPR ranking at the end of the season) will really go down and not up.
Now, if you want to argue that in tennis we should not care about games won/lost but only about whether someone actually won a match - you may have an argument. Such a system will have its own set of problems, mainly that you will have only two outcomes of any match (a win or a loss) vs. a set of outcomes (depending on games won/lost difference) and therefore there will be way less data for algorithm to crunch.
Well, it flawed because, to use your (and the OP's) example the statistical chance that your example 3.89 player will meet only players of his or lower ranking 15 times in a row is less than 3 one thousanths of one percent.
In other words that reality exists only in strawman arguments like your post, not in the real world.
You scoff in your second bolded statement at the idea of W/L record being meaningful. My answer: if it works for Pros, why use a convoluted system for everyone else? If you lose in the first round of Wimbledon, it doesn't matter to your ATP points if it is to Fed or a Lucky Loser, you get the same credit.