English Chess Forum

Martin, Players improve and some players improve rapidly, but I don't really see the relevance of the past grading history. All we need to know is that Knightie starts at 206 and ends at 230. He goes from 2245 to 2425 He has got a z score of 4 by selecting engine moves at a rate associated with a 30...

David,
I don’t really understand what you are trying to say here. For Ken Regan’s test the standard deviation is based on the entire population. So if knightie is 206 that is 2245 and he would have to select engine moves at a rate associated with a player rated 3045 to get a z score of 4.
Matt

Mick, I don't know the answer to that question, but the captains were told that those detected as cheating were spread across the divisions and that there wasn't a noticeable bulge anywhere. The evidence that I have seen would bear this out, but that may be because I am only aware of a certain subse...

the claim that there are players with stable ratings who can fluctuate on their raw strength by 2 standard deviations between tournaments is equivalent to the claim that there are stable 2200s who - when they are on form - could be expected to hold their own in e.g. the Grand Swiss and get 50% or b...

Roger, We are talking about knowing theory that no 2300 has ever played (in a game in a database) and and our opponent playing down the whole line and then that being repeated again and again. We don't even know if David's example meets that criteria (because we don't know how the game continued). P...

Yes, so long as the tool knows that you're in known theory..... Which must be a genuinely very difficult task these days. True. I remember playing the following line against Francis Rayner at Scarborough in 2015. [Event "Scarborough Open"] [Date "2015.10.25"] [White "Walker, David"] [Black "Rayner,...

Just out of interest - I don't know that much about what Ken Regan does, but do we know how accurate his system is, and if so, how do we know? Plenty of reasons to trust. He's a sensible, knowledgable person Oh, it's not this that I'm asking about, I take that to be the case. I was just unsure abou...

David, How about I show that my grade was rounded down to 180 and was actually 180.4 and so 2053 should be used as my rating and consequently my z score should be 3.99 - is that still enough? I am trying to demonstrate there are quite a few grey areas and people can legitimately have differing views...

Does a z-score of 4 really equate to an 800 point rating boost? I know that the ELO standard deviation is supposed to be 200, but this z-score is in a different domain (basically measuring actual moves matched against expected matches I believe). There is a draft paper by Dr Regan in which he gives...

The point of the margin is specifically to take into consideration these kind of fluctuations, so in my opinion, no! OK so let try another example. Bob Bunny is a junior rated 1500. He has a z score of 4 in the JNCL over his first 6 games (i.e selecting computer moves at a rated associated with a 2...

Martin, Your grading history 181D Jan 2020 181D July 2019 179B Jan 2019 177A July 2018 181B Jan 2018 180A July 2017 181A Jan 2017 186A July 2016 190B Jan 2016 188C Jul 2015 185A Jan 2015 179A July 2014 178A Jan 2014 171A July 2013 193B Jan 2013 190C July 2012 187B Jan 2012 183B July 2011 180B July 2...

Or even more solid evidence - I spent maybe 5 years playing 20+ ecf better underlying in the 4NCL than evening leagues. Very solid documentation. If I'd then had a great 4NCL season and got a 4 sigma notification based on a grade derived from my evening league performances then you'd hope trivial t...

The point of the margin is specifically to take into consideration these kind of fluctuations, so in my opinion, no! OK so let try another example. Bob Bunny is a junior rated 1500. He has a z score of 4 in the JNCL over his first 6 games (i.e selecting computer moves at a rated associated with a 2...

This is what worries about the grade uncertainties. Supposing you set Z=4 for the 4NCL online. Then imagine everyone you try and ban lodges an appeal saying 'I play relatively better online/faster time limits, and the season should only be viewed as an Z=3.5 even. That's underneath your self impose...

Martin,
So, this is exactly the question I am posing to the 4NCL myself.
I think the 4NCL would say that they were looking for a figure round about 4 to validate/support a Lichess ban, but a higher figure, lets say 5 to initiate a 4NCL ban.