English Chess Forum

It really doesn't matter what the overall standard deviation is because we only care about the part of the distribution where players are massively outperforming their rating. I'm sorry but this indicates a failure to grasp the subject. It really does matter. It matters because, if there are irregu...

Roger, I think it is pretty well established that average online performance is lower than average OTB performance. This is reflected in the 4NCL graphs. We could easily incorporate this into the Regan results by lowering everyone's rating by 100 points and increasing their z scores by circa 0.5 Al...

The graph reflects the difference between actual online performance and expected OTB performance. Except, Matt, that you answered my earlier question, " Do you believe that average online and OTB performance is indeed equal? " by saying " I believe the online performance will be lower ". Let's assu...

Roger, I believe the online performance will be lower, so the 4NCL underestimates cheating. I believe that is right and proper and gives more protection to players from wrongful accusations. Excellent, Matt, we're making progress. Now, as regards the OTB graph, I hope you'll agree that the data ref...

Roger Lancaster wrote " As to the respective qualities of play [measuring online, sans cheating, against over-the-board] my gut feel tends to be with Joseph" So the evidence that you presented as showing the 4NCL exaggerated cheating, your gut feeling now suggests underestimates cheating. Matt, you...

Thanks also to John. My problem is the widespread belief that Ken Regan's methodology was handed down to Moses on Mount Sinai and must therefore - something that, in fairness, Ken is at pains to deny - be correct in every last detail. That's the same mindset as the Post Office directors who decided ...

Thanks to Joseph and Paul for their comments earlier. As to the respective qualities of play [measuring online, sans cheating, against over-the-board] my gut feel tends to be with Joseph although I have no evidence to support this - except that there's a study by three Dutch academics [one an IM] of...

As I said, I find it hard to believe the people responsible for the underlying statistical treatments of the data available to them - both in the 4NCL and the wider online & otb chess world - have somehow got it basically wrong. John, I don't want to dwell on this forever but my comments yesterday ...

John, the most obvious flaw with the original graph is that it treats two distributions as having the same mean and SD despite the fact that, while one has 68% of the data falling within the 1>z>-1 range as expected for a Normal distribution, the other has only 58%. All else follows from that.

Paul, part of my argument was that the online data showed - as I felt might intuitively have been expected - a greater dispersion [variously known also as variation, scatter or spread] than the over-the-board data. The intuitive reasons were more or less those mentioned by Matt - primarily distracti...

Matt, the contention that I have said, or believe, that "the data is more spread out because players are more likely to objectively perform 600 points above their rating online" is a fictional product of your imagination and I do not intend to keep on rebutting it here ad nauseam. These accusations ...

Matt I can't actually work out how you arrive at that conclusion which is neither what I've said nor what I believe. The gist of Alex's article was that a number of online players cheat and thereby get much better online results than appears plausible from their over-the-board performances, whether ...

No, just to be clear, that's definitely not what I'm saying. I'm saying that the displayed distribution for online players [some of whom we all agree must be cheating] shows just 58% of values in the range 1>z>-1. If the distribution for online players [without cheating] possessed the same mean and ...

Matt Yes, broadly - but only broadly - agreed. One is left to speculate what the distribution for the online participants would have been, in the event that none had cheated. Let's leave aside the complication of different people [OTB participants versus online participants] and I think there are em...

"... whether a Normal distribution is likely to give a reliable result when it is most unlikely that the data actually conforms to a Normal distribution." I believe whether or not a data set conforms to a Normal distribution can be tested for. The extract reproduced by John was intended as a maxim ...