Originally Posted by NumbersGuy
Schmke, when you say "give less weight to matches between mis-matched players, unless there is an upset of course" (italics added), is that really what you meant? Because a tank job looks exactly like an upset to the computer. I think the computer already throws out matches when the players/teams are more than 0.5 apart. I think you touched on a better idea for eliminating tanking, which to eliminate matches that are too far from the "expected range". It would be simple enough for the USTA to do some calculations to identify match results that are outside, say, a 95% frequency of occurrence, and eliminate them from the NTRP calculation on the suspicion of tanking or injury or other unreliable indicator of ability. Yes that would wipe out the occasional wonderful and well-earned upset, but for every one of those I suspect it would also eliminate 20 tank jobs.
Yes, both of the items I mentioned need to be used.
For example, if in a 4.0 match, an about to be bumped to 4.5 (rated very near 4.5) plays a low-end 3.5 that is playing up (rating very near 3.5), he should in theory win 0 & 0. But if he happens to give up a game and wins 1 & 0 an unweighted system would ding the winning player pretty severely. This is a match that should be given less weight because the opponents are far apart.
But you don't want to discredit the match entirely, so if the match does get closer or perhaps even the lower rated player wins, you want to give it more weight. BUT, you also need the "throw a match" check which would look at the "rating profile" of both players and if this match looks like an anomaly, either throw it out or give it less weight.