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AylerKupp
Member since Dec-31-08 · Last seen Mar-02-15
About Me (in case you care):

Old timer from Fischer, Reshevky, Spassky, Petrosian, etc. era. Active while in high school and early college, but not much since. Never rated above low 1800s and highly erratic; I would occasionally beat much higher rated players and equally often lose to much lower rated players. Highly entertaining combinatorial style, everybody liked to play me since they were never sure what I was going to do (neither did I!). When facing a stronger player many try to even their chances by steering towards simple positions to be able to see what was going on. My philosophy in those situations was to try to even the chances by complicating the game to the extent that neither I nor the stronger player would be able to see what was going on! Alas, this approach no longer works in the computer age. And, needless to say, my favorite all-time player is Tal.

I also have a computer background and have been following with interest the development in computer chess since the days when computers couldn't always recognize illegal moves and a patzer like me could beat them with ease. Now itís me that canít always recognize illegal moves and any chess program can beat me with ease.

But after about 4 years (a lifetime in computer-related activities) of playing computer-assisted chess, I think I have learned a thing or two about the subject. I have conceitedly defined "AylerKupp's corollary to Murphy's Law" (AKC2ML) as follows:

"If you use your engine to analyze a position to a search depth=N, your opponent's killer move (the move that will refute your entire analysis) will be found at search depth=N+1, regardless of the value you choose for N."

Iím also a food and wine enthusiast. Some of my favorites are German wines (along with French, Italian, US, New Zealand, Australia, Argentina, Spain, ... well, you probably get the idea). One of my early favorites were wines from the Ayler Kupp vineyard in the Saar region, hence my user name. Here is a link to a picture of the village of Ayl with a portion of the Kupp vineyard on the left: http://en.wikipedia.org/wiki/File:A...

You can send me an e-mail whenever you'd like to aylerkupp(at)gmail.com.

And check out a picture of me with my "partner", Rybka (Aylerkupp / Rybka) from the CG.com Masters - Machines Invitational (2011). No, I won't tell you which one is me.

-------------------

Analysis Tree Spreadsheet (ATSS).

The ATSS is a spreadsheet developed to track the analyses posted by team members in various on-line games (XXXX vs. The World, Team White vs. Team Black, etc.). It is a poor man's database which provides some tools to help organize and find analyses.

I'm in the process of developing a series of tutorials on how to use it and related information. The tutorials are spread all over this forum, so here's a list of the tutorials developed to date and links to them:

Overview: AylerKupp chessforum (kibitz #843)

Minimax algorithm: AylerKupp chessforum (kibitz #861)

Principal Variation: AylerKupp chessforum (kibitz #862)

Finding desired moves: AylerKupp chessforum (kibitz #863)

Average Move Evaluation Calculator (AMEC): AylerKupp chessforum (kibitz #876)

-------------------

ATSS Analysis Viewer

I added a capability to the Analysis Tree Spreadsheet (ATSS) to display each analysis in PGN-viewer style. You can read a brief summary of its capabilities here AylerKupp chessforum (kibitz #1044) and download a beta version for evaluation.

-------------------

Chess Engine Evaluation Project

Some time ago I started but then dropped a project whose goal was to evaluate different engines' performance in solving the "insane" Sunday puzzles. I'm planning to restart the project with the following goals:

(1) Determine whether various engines were capable of solving the Sunday puzzles within a reasonable amount of time, how long it took them to do so, and what search depth they required.

(2) Classify the puzzles as Easy, Medium, or Hard from the perspective of how many engines successfully solved the puzzle, and to determine whether any one engine(s) excelled at the Hard problems.

(3) Classify the puzzle positions as Open, Semi-Open, or Closed and determine whether any engine excelled at one type of positions that other engines did not.

(4) Classify the puzzle position as characteristic of the opening, middle game, or end game and determine which engines excelled at one phase of the game vs. another.

(5) Compare the evals of the various engines to see whether one engine tends to generate higher or lower evals than other engines for the same position.

If anybody is interested in participating in the restarted project, either post a response in this forum or send me an email. Any comments, suggestions, etc. very welcome.

-------------------

Ratings Inflation

I have recently become interested in the increase in top player ratings since the mid-1980s and whether this represents a true increase in player strength (and if so, why) or if it is simply a consequence of a larger chess population from which ratings are derived. So I've opened up my forum for discussions on this subject.

I have updated the list that I initially completed in Mar-2013 with the FIDE rating list through 2014 (published in Jan-2015), and you can download the complete data from http://www.mediafire.com/view/pfbnt.... It is quite large (114 MB) and to open it you will need Excel 2007 or later version or a compatible spreadsheet since several of the later tabs contain more than 65,536 rows.

The spreadsheet also contains several charts and summary information. If you are only interested in that and not the actual rating lists, you can download a much smaller (598 KB) spreadsheet containing the charts and summary information from here: http://www.mediafire.com/view/pfbnt.... You can open this file with a pre-Excel 2007 version or a compatible spreadsheet.

FWIW, after looking at the data I think that ratings inflation, which I define to be the unwarranted increase in ratings not necessarily accompanied by a corresponding increase in playing strength, is real, but it is a slow process. I refer to this as my "Bottom Feeder" hypothesis and it goes something like this:

1. Initially (late 1960s and 1970s) the ratings for the strongest players were fairly constant.

2. In the 1980s the number of rated players began to increase exponentially, and they entered the FIDE-rated chess playing population mostly at the lower rating levels. The ratings of the stronger of these players increased as a result of playing weaker players, but their ratings were not sufficiently high to play in tournaments, other than open tournaments, where they would meet middle and high rated players.

3. Eventually they did. The ratings of the middle rated players then increased as a result of beating the lower rated players, and the ratings of the lower rated players then leveled out and even started to decline. You can see this effect in the 'Inflation Charts' tab, "Rating Inflation: Nth Player" chart, for the 1500th to 5000th rated player.

4. Once the middle rated players increased their ratings sufficiently, they began to meet the strongest players. And the cycle repeated itself. The ratings of the middle players began to level out and might now be ready to start a decrease. You can see this effect in the same chart for the 100th to 1000th rated player.

5. The ratings of the strongest players, long stable, began to increase as a result of beating the middle rated players. And, because they are at the top of the food chain, their ratings, at least so far, continue to climb. I think that they will eventually level out but if this hypothesis is true there is no force to drive them down so they will stay relatively constant like the pre-1986 10th rated player and the pre-1981 50th rated player. When this leveling out will take place, if it does, and at what level, I have no idea. But a look at the 2013 ratings data indicates that, indeed, it may have already started.

You can see in the chart that the rating increase, leveling off, and decline first starts with the lowest ranking players, then through the middle ranking players, and finally affects the top ranked players. It's not precise, it's not 100% consistent, but it certainly seems evident. And the process takes decades so it's not easy to see unless you look at all the years and many ranked levels.

Of course, this is just a hypothesis and the chart may look very different 20 years from now. But, at least on the surface, it doesn't sound unreasonable to me.

But looking at the data through 2014 it is even more evident that the era of ratings inflation appears to be over. The previous year's trends have either continued or accelerated; the rating for every ranking category, except for possibly the 10th ranked player (a possible trend is unclear), has either flattened out or has started to decline.

Any comments, suggestions, criticisms, etc. are both welcomed and encouraged.

-------------------

Chessgames.com Full Member

   AylerKupp has kibitzed 7598 times to chessgames   [more...]
   Feb-28-15 Magnus Carlsen (replies)
 
AylerKupp: <achieve> <schweigzwang> correctly indicated my opinion. I think that we all have an "inherent playing strength" (IPS), its just unfortunate that we haven't figured out a way to measure it. All we know how to measure is relative playing strength, and even that might be
 
   Feb-28-15 AylerKupp chessforum (replies)
 
AylerKupp: <Tiggler> Sorry about that omission. I think that lowering the ratings floor will cause not only a ratings inflation but an increase in the rate of ratings inflation because the majority of the ratings of those at the bottom of the ratings population are too optimistic. When
 
   Feb-26-15 FIDE Grand Prix Tbilisi (2015) (replies)
 
AylerKupp: <AsosLight> Yes, but being ugly and essential are not contradictory. At least that's what I hope my wife would say.
 
   Feb-26-15 Fischer vs Gligoric, 1962 (replies)
 
AylerKupp: <Howard> According to Stockfish 6, after 43.Kf3 Black has two forced mates at d=36 (the second mate was originally discovered at d=28 in 17 moves) : 1. [-M10] : 41...Qf5+ 42.Rf4 Rd3+ 43.Qe3 Rf1+ 44.Rf2 Qh3+ (I've never seen such a perfect coordination of heavy pieces.) ...
 
   Feb-23-15 Robert James Fischer (replies)
 
AylerKupp: <<RookFile> Healthy or not, I think that Tal is probably in the running for the title of "Most Entertaining Player", both on and off the chessboard.
 
   Feb-23-15 Svidler vs D Andreikin, 2015 (replies)
 
AylerKupp: <<Mr. V> is there another winning method of keeping the white rook on the e-file, to repel the black king?> I don't know. The approach of keeping the rook on the e-file cutting off the Black king from the k-side is certainly logical. But White probably needs to have a ...
 
   Feb-23-15 Pelikan vs W J Muhring, 1936 (replies)
 
AylerKupp: <SimplicityRichard> If you like your new "best-mate" Stockfish 5 you might consider upgrading to Stockfish 6. It has incorporated the changes for the Stockfish 5-based mate finder, additional enhancements, and (finally!) official Syzygy tablebase support. It is currently ...
 
   Feb-22-15 O'Kelly vs J Penrose, 1962 (replies)
 
AylerKupp: For some reason after 27.Bd3 Stockfish 6 at d=30 prefers 27...Bxf2+ instead of 27...Kg4. And after 27...Kg4 28.Be2, also at d=30, it still prefers 28...Bxf2+. Since either ...Kg4 or ...Bxf2+ lead to the same result, I'm puzzled why Stockfish would prefer ...Bxf2+ which should lead
 
   Feb-21-15 J Dill vs Ravishen Singh, 2008 (replies)
 
AylerKupp: <HeMateMe> Don't you just hate it when that happens?
 
   Feb-21-15 Guimard vs Fischer, 1960 (replies)
 
AylerKupp: <jerseybob>, <Fusilli> My Stockfish 6 also evaluates 15.Nxg5 as White's best move, but only at [-0.75] . Here are Stockfish's top 3 lines at d=35: 1. [-0.75] : 15.Nxg5 d5 16.Qh7+ Kf8 17.Ngf3 e5 18.Nh4 Nc6 19.Ng6+ Kf7 20.f3 Be6 21.Rh4 Qg8 22.Qxg8+ Kxg8 23.Ke2 Rf7 24.Re1
 
(replies) indicates a reply to the comment.

De Gustibus Non Disputandum Est

Kibitzer's Corner
< Earlier Kibitzing  · PAGE 48 OF 48 ·  Later Kibitzing>
Dec-25-14
Premium Chessgames Member
  morfishine: <AylerKupp> I hope you have a very enjoyable Christmas and a Happy New Year!
Dec-26-14  cormier: Joyeux NoŽl ...
Dec-29-14
Premium Chessgames Member
  AylerKupp: Thank you all. And the same to all of you.
Feb-02-15
Premium Chessgames Member
  AylerKupp: BTW. I have updated the list that I initially completed in Mar-2013 with the FIDE rating list through 2014 (published in Jan-2015), and you can download the complete data from http://www.mediafire.com/view/pfbnt.... It is quite large (114 MB) and to open it you will need Excel 2007 or later version or a compatible spreadsheet since several of the later tabs contain more than 65,536 rows.

The spreadsheet also contains several charts and summary information. If you are only interested in that and not the actual rating lists, you can download a much smaller (598 KB) spreadsheet containing the charts and summary information from here: http://www.mediafire.com/view/pfbnt.... You can open this file with a pre-Excel 2007 version or a compatible spreadsheet.

Refer to the header in this page for more information. But looking at the data through 2014 it is even more evident that the era of ratings inflation, no matter how you define it, appears to be over. The previous year's trends have either continued or accelerated; the rating for every ranking category, except for possibly the 10th ranked player (a possible trend is unclear), has either flattened out or has started to decline.

Feb-16-15
Premium Chessgames Member
  Tiggler: <AylerKupp> I was looking through your profile for an active link to be able to download your ATSS, but could not find what I was looking for. I see a version that displays analysis in pgn viewer, but what I was hoping to find is a version that reads .pgn and displays a tree in spreadsheet form.
Feb-16-15
Premium Chessgames Member
  AylerKupp: <Tiggler> I do have the bits and pieces that do what you were hoping for but they are not integrated. I have a version of the ATSS called the SGSS (Supplementary Games spreadsheet) intended to display games rather than analyses. I have used this to capture the games that are typically posted at the beginning of either a Challenge Game or a Team vs. Team Game but it is a manual process that uses a Word template where I manually enter some of the information (poster, game date, result, players and their ratings, etc.), copy the game in *.pgn format from the game page to the Word template, do some manual clean-up, create a Word table of the *.pgn game, and copy it into the SGSS. I developed some Word and Excel macros to help but it is still a labor-intensive and time consuming process, not to mention somewhat error-prone.

I have also developed a Word macro that parses a *.pgn file and generates a *.csv file which in turn can be loaded into the equivalent of the SGSS. I have tested it reasonably well but there are so many possible PGN formats that I can't guarantee that it will work 100% of the time. The biggest problem at the moment is that it currently it does not handle comments in the *.pgn file and I just haven't had a chance to fix that.

Another problem is that different games use different PGN fields and a spreadsheet requires that the number of fields be known in advance so that the first move of every game starts on the same column so that the tree-like structure can be displayed. I can generate a suitable Excel template with the viewer easily enough with the fields that you think would be generally desired (player's names and ratings, game date, result, game type (OTB, correspondence, blitz, computer, etc.). Then using would be a 2-step process, somewhat complicated and not particularly user-friendly:

1. Create the *.csv file:

a. Copy the *.pgn file into the blank Word template containing the parsing macro, save it as a Word *.doc file.

b. Press Ctrl-P (for parse) to run the parsing macro. This will scan the *.pgn format games in the *.doc file and create a *.csv file in the same folder as the *.doc file and with the same name, except with the *.csv file extension.

2. Create the spreadsheet file.

a. Open Excel template file.

b. Open (from within Excel) the *.csv file.

c. Copy the contents of the *.csv template into the Excel template file.

If the above hasn't discouraged you I could create an Excel template file with the PGN fields that I think would be the most useful and upload the templates to a file sharing service from where you can download them and try to use them. But I can't get to that until later this week since I have some out of town company visiting and need to spend time with them.

Feb-16-15
Premium Chessgames Member
  Tiggler: <AylerKupp> Thanks for the detailed reply. Actually, what I need is simpler than parsing a full .pgn . I just need to get the moves (after stripping off any header) into .csv . I would have comments after some moves, however.

Here is what I want it for. I have a big .pgn file containing analysis of our GMARK game from move 36 onward, with many branches. So many branches that it is hard to visually follow the .pgn, to check that all branches are correctly ordered and terminated with checkmate, or a tablebase result, or a confirmed engine mate announcement. Some lines contain engine evals other than checkmate, but these are always viewed as interim, and no line can end there.

The goal is to demonstrate an exhaustive analysis to the fastest checkmate. A very large task, even starting from move 36. Incomplete nearly two months after the game ended!

Feb-16-15
Premium Chessgames Member
  Tiggler: I should have said that the .pgn is generated by Arena.
Feb-17-15
Premium Chessgames Member
  morfishine: <Aylerkupp> Interesting, I had never read your 'Bottom Feeder' hypothesis at the time I posted my 'Big Fish get Bigger' conclusion.

The term 'Ratings Inflation' may be misleading since one could think in terms of increasing the money supply, which increases prices. On the other hand, an increase in the # rated players means more rating points are available "for the taking".

If one really wanted to see if individual ratings have been artificially inflated, one must use the various systems/formulas over time to see the difference. If one finds the same player has a different rating at the same time, then ratings have been inflated

Skewed scoring plays a part too. When I play on the internet, my opponent setting is set for same rating to +500 so I never play someone rated lower than me. So, I may play someone rated 300 more than me and lose 3 straight games and a total of 12 rating points, but then I win one and gain 20 points for a net +8 for the afternoon's effort. I only won 1 out of 4 games, yet gained 8 points. Another example, I played an opponent who was rated 340 points higher than me. I forced a draw and gained 4 points.

Or looking at one GM victory, any victory: Lets say he gains 2 points, Is he "2 points stronger?". I don't think so, strength cannot be measured in points though its an indicator over time and the best thing we got for a metric

*****

Feb-17-15
Premium Chessgames Member
  AylerKupp: <Tiggler> OK, knowing that the PGN was generated by Arena is a help, since Arena is consistent (and PGN-standard compliant) on how comments are generated. My motivation for the parser was for downloading the ICCF game archives and attempting to generate one spreadsheet for each year. And if you think that your *.pgn files are big you should see the *.pgn files for the recent ICCF archives! (the *.pgn file for the 2013 archives, the last archive that I fully downloaded, consists of 52,621 games and is almost 148 MB) But the comments in the ICCF PGN files are not necessarily compliant with the PGN standard; sometimes they start and end with curly brackets, sometimes with parenthesis, and they are often nested, even though comment nesting is technically not allowed per the PGN standard. But I can probably update the parser to handle PGN-compliant comments easily enough, it's only when I try to make it sufficiently robust to handle non-PGN-compliant comments without either crashing of losing no more than the current game's score that it gets messy.

One question that I've been struggling with is what to do with the comments. In the ATSS and SGSS I had comments attached to the individual cells containing the moves and, if the comments are unstructured and free form, that's all I can think of doing. But in the case of Arena *.pgn files they contain the evaluation, search depth, and calculation time for the move in seconds; all valuable information to retain in a structured way. So I thought that in those cases I would in addition generate a second *.csv file containing one row each for the move number, White's move, evaluation after White's move, search depth for White's move, calculation time for White's move, Black's move, evaluation after Black's move, search depth for Black's move, and calculation time for Black's move. Then it would be easy to load that *csv file into Excel, chart the evaluations, calculate statistics, see the variations and calculation time per move, etc. What do you think of these ideas?

Feb-17-15
Premium Chessgames Member
  AylerKupp: <morfishine> Yes, one point I tried to make was that there are several definitions or ratings "inflation" and when discussing them one must make sure that everyone is talking about the same thing. If by "inflation" one is just talking about an overall increase in ratings then it's easy to see that this has clearly taken place; all one has to do is look at the number of players rated above 2700, above 2600, etc. But when one refers to "inflation" as an overall increase in ratings <without> a corresponding increase in playing strength, that is a much more difficult thing to show if for no other reason that I don't know of a good way to measure <intrinsic> playing strength. Oh, I think that one can subjectively say that, Kasparov in his prime was a stronger player than Euwe or Polugaevsky in their prime and probably even get a consensus agreement on that. But unless it is an "obvious" comparison that is difficult to do. It is this second definition of inflation that is analogous to monetary inflation in the sense that each rating point is not as valuable as it used to be.

Or maybe the concept of "intrinsic playing strength" is the problem; playing strength may not be determinable except in comparison with other players. And so it may be particularly difficult to determine the intrinsic playing strength of a particular player at 25 years of age and compare it with the intrinsic playing strength of the same player at 35 years of age. His/her rating at 35 might be higher than his/her rating at 25 but does that necessarily mean that they were intrinsically stronger at 35 than at 25? Or their rating at 55 may be lower than their rating at 35 but does that necessarily mean that they were stronger at 35 than at 55? And even if we could subjectively answer those questions we are left with the problem of quantifying it; i.e. how much better or worse was a specific player at 25, 35, and 55?

But we need to remember that when making comparisons or broad statements we need to take a look at many games. In one or a small number of games any result is possible, and for every single example that one finds someone else will be able to find a single counter-example. Another way of saying is that the differences must be statistically significant; i.e. the probability that the observed results were obtained strictly by chance must be very small.

Feb-17-15
Premium Chessgames Member
  Tiggler: <AylerKupp> <But in the case of Arena *.pgn files they contain the evaluation, search depth, and calculation time for the move in seconds; all valuable information to retain in a structured way. So I thought that in those cases I would in addition generate a second *.csv file containing one row each for the move number, White's move, evaluation after White's move, search depth for White's move, calculation time for White's move, Black's move, evaluation after Black's move, search depth for Black's move, and calculation time for Black's move. Then it would be easy to load that *csv file into Excel, chart the evaluations, calculate statistics, see the variations and calculation time per move, etc. What do you think of these ideas?>

I always suppress the automated comments from Arena, so the only comments in my files are the ones I enter manually: Usually at most the evals and the first move of each pv. And only for opponent's next move, because those are the branches that might need to be checked, unless they are short mates.

Not sure your method works, because the tree is two dimensional already, so you can't link cells to rows, only to single cells in another sheet - but that ought to work fine: moves on one sheet and corresponding data in the corresponding cells on another sheet. You would have to select the cell to read long comments in the command line.

Feb-17-15
Premium Chessgames Member
  Tiggler: On inflation. I am not certain that there has been any, though certainly there is no "gold standard", so no reason the currency might not wander over time.

Consider this, though: look up the fastest track times for, say, 400 metres, in 1972. (The year of Fischer's highest rating). Probably you will find that in 2014 there are at least several 100 recorded times that are faster than the 10th fastest time of 1972. Similar to the situation in chess, right? Yes, but not inflation because the stopwatch does not lie. The change is due to better equipment (shoes, track), better nutrition, and better training, and to the larger number of competitors. Completely analogous to chess? Maybe it is.

Feb-18-15
Premium Chessgames Member
  Tiggler: If I were to follow your example, and name myself after a white wine region, I would be the <MaconLooney>.
Feb-18-15
Premium Chessgames Member
  Tiggler: On red wine days, I'd be <HoHoHoMeDoc>.
Feb-18-15
Premium Chessgames Member
  Tiggler: After dinner, I mellow quite a bit and become the <BarsacBalzac>.
Feb-21-15
Premium Chessgames Member
  AylerKupp: <Tiggler> I think that on Feb-18-15 you might have had a little bit too much of MaconLooney, HoHoHoMeDoc, or BarsacBalzac (or possibly all 3). I hope that you enjoyed them!

And next time try to find some AylerKupp Trockenbeerenauslese and let me know what it's like. Too rich for my blood or wallet., even with my eponymous discount.

Feb-25-15
Premium Chessgames Member
  Tiggler: I hope that your visitors went away happy ... or at least that they went away.
Feb-26-15
Premium Chessgames Member
  AylerKupp: <Tiggler> Thank you. Yes, they went away and I think that they were happy ... to have gone away.
Feb-26-15
Premium Chessgames Member
  AylerKupp: A discussion started approximately here: FIDE Grand Prix Tbilisi (2015) (kibitz #424) about my Bottom Feeder hypothesis but that is clearly off-topic for that page. So I am suggesting that, if anyone is interested, we continue the discussion in this forum at least until a more suitable place is found.
Feb-26-15
Premium Chessgames Member
  Tiggler: Repost from the Hans Arild Runde page of two years ago:

Hans Arild Runde (kibitz #6302)

<Feb-22-13
Tiggler: <twinlark>: <<frog>

I'm shocked. I made a similar assertion last year...>

I looked back at that page and the comment was about ratings floors, which is a whole different topic. Ratings floor does cause inflation (it was introduced to stop deflation at the low end). If the floor is lowered then not so much inflation results. If happens because if there is a wall at one side, the sand gets a net flow in the other direction: average ratings increase.>

Feb-27-15
Premium Chessgames Member
  AylerKupp: <Tiggler> I never thought much about the lowering of the ratings floor but, now that you mention it, in my response to <devere> (see FIDE Grand Prix Tbilisi (2015) (kibitz #480)) I agreed with what he said in that most of the time if a rated player loses or draws against an unrated player his rating does not go down, but if an unrated player beats a rated player then the unrated player's rating goes up. This asymmetry would cause an upwards push on the ratings that will eventually push up the ratings of the top rated players the more unrated players enter the population. So I think that in your response to <frogbert> you got it backwards; lowering the ratings floor will eventually cause an <increase> in the rate of ratings inflation, not a decrease.

Once FIDE stops lowering the ratings floor the effect should not be as pronounced since the number of unrated players that enter the population should be much less and this should help stabilize the ratings. But the initial ratings for unrated players are much more volatile than the ratings for established players because of the K-factor used (40 for an unrated player until he's played 30 games, 20 for players rated below 2400, and 10 for players rated 2400 and above, even if their rating later drops below 2400). The later K-factor of 10 for the top players means that their rating changes will be less than for equivalent performances by unrated players and players below 2400, so the effects will be seen more slowly at the top levels.

And FIDE changed their ratings regulations effective July 1, 2014; the K-factors prior to that time used to be 30 for unrated players and 15 for players rated 2400, so their ratings volatility was less. This higher ratings volatility for unrated and lower rated players will to a certain extent compensate for the lack of additional unrated players entering the population as a result of further lowering of the ratings floor.

Feb-27-15
Premium Chessgames Member
  Tiggler: <So I think that in your response to <frogbert> you got it backwards; lowering the ratings floor will eventually cause an <increase> in the rate of ratings inflation, not a decrease.>

You don't explain why you think this. I think the opposite because the effect is proportional to the number of players at the boundary. With the floor below the average (and modal) rating, the number of these players has decreased. There is also a separate issue: the lower the floor, the less, and more delayed, is the effect at the highest ratings, which are the only ones where inflation, if it exists at all, is important.

I believe there are other effects that are more significant. The most important of these now is the 400-point rule, which tends to inflate the higher ratings and deflate the lower ones.

Feb-28-15
Premium Chessgames Member
  AylerKupp: <Tiggler> Sorry about that omission. I think that lowering the ratings floor will cause not only a ratings inflation but an increase in the rate of ratings inflation because the majority of the ratings of those at the bottom of the ratings population are too optimistic. When most of these optimistically-rated players meet established players with the correct rating, they will lose more often than not and cause the ratings of the established players to rise and reflect a strength that they don't really have. This will cause these players to meet the next set of established players above them and, because their ratings were inflated, they will lose more often than not (reverting to their original ratings) and the ratings of the players that defeated them will increase, causing them to meet even stronger players, etc. And the cycle will repeat itself and propagate itself upwards.

All this, of course, takes time. That's one possible reason why if you look at the data you will see that the downward trend for player ratings starts earlier for the lower rated players and eventually catches up (has caught up) with the higher ranked players.

I don't know if you are an Excel user but, if you are, you should download the summary spreadsheet using the link I provided in my forum header. There are a lot of charts included and a picture is worth a thousand words. Probably more in my case.

And, since we are on the subject, I don't think that the 400-point rule has much effect on the ratings. After all, the Elo P(Win) for a 400-point rating differential is 0.92 so the likely winner of the game (the stronger player) would not gain that many more rating points

But, since we are on the subject, why do you think that the 400-point rule would tend to inflate the higher ratings and deflate the lower ones? I would think that if there is a 700-point rating differential between 2 players and the stronger player wins (which would be the likely case), then the fact that the rating differential is considered to be 400 points means that the winner will gain 0.91 rating points and if the full 700 point ratings differential is used the winner will gain only 0.17 points. Given the number of times that players with a 700 point differential play against each other, I don't think the additional 0.74 rating points gained by the stronger player if the 400-point rule were used would be significant in the overall scheme of things. But that's just my opinion, no firm basis for it.

Feb-28-15
Premium Chessgames Member
  Tiggler: < I would think that if there is a 700-point rating differential between 2 players and the stronger player wins (which would be the likely case), then the fact that the rating differential is considered to be 400 points means that the winner will gain 0.91 rating points and if the full 700 point ratings differential is used the winner will gain only 0.17 points.>

I cannot follow your argument, because the correct number of ratings points in the case you describe is +0.8, instead of I guess <0.1. My opinions are based on simulations, using, guess what Excel. These show that if all players get, on average, results that reflect their ratings, then the distribution of ratings will spread over time, with the highest ratings climbing and the lowest falling. This is just due to the statistical random walk. In order to stabilize this effect, one has to assume that the higher rated player will underperform the rating difference by about 2%. This is sufficient to stabilize the distribution. The mechanism can be referred to as a mean-regression effect.

This is the simulation result if there is no ratings floor and no 400-point rule. Introduce the 400-point rule and the simulation blows up: the highest ratings march away and reach 4000 very fast after a few 1000 iterations.

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