Originally Posted by Islandtennis
One thing to remember is that the primary use of benchmarks is to equate NTRP levels across local areas. The district, sectional, and national playoffs is the only time (in league play) that people play out of their local area. It attempts to do the impossible of making a 3.5 in CA similar to a 3.5 in NY; or a 3.5 in one part of GA similar to a 3.5 in another part of GA. While not perfect, it does work better than having no equalizing in place.
Great discussion! My thoughts are very much in-line with what dizzlmcwizzl's was saying, and I agree with the above as well. But to me, "not perfect" is the key here: I feel that NTRP's attempt to "equate levels across local areas" is based on a faulty premise. A set of faulty premises actually: the algorithm makes statistical determinations based on a sample size that is too small to support such determinations; on top of that, the sample itself is likely to be NOT representative of the "average" level of play in a given area. Then the problem is compounded by giving this questionable "denominator" too much weight.
I'm actually not sure that this works better than having no equalizing in place, even for the stated purpose of equating NTRP levels across local areas. As for the role this plays in calculating individual year-end DNTRP: while benchmark recalculation produces a ripple effect for all players, it almost certainly affects players who happened to play directly against benchmarks in a non-linear way, and can result in some odd NTRP outcomes for such players. It appears that one blow-out loss (or win... it goes both ways) against a benchmark player might outweigh a player's entire record during the year.