Here's commentary on the Carlsen/Anand double-blunder: http://youtu.be/6K86f27uuP0?t=14m36s
It's not easy to see.
When Grandmasters Blunder: Even the best make mistakes
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Re: When Grandmasters Blunder: Even the best make mistakes
#12Hi guys, author here. I'll be monitoring this thread for the rest of the evening. Happy to answer any questions.
What time controls were you looking at? I'm half-jokingly wondering if the big dip of correct moves in the upper 2800 range is Nakamura's crazy opening style :) (He's rated upper 2800's in blitz and rapid)
Re: When Grandmasters Blunder: Even the best make mistakes
#13Grandmasters blunder more often than this. I would venture to say that what correlates with blunders more so than rating is time. Error rate goes way up in Blitz and Rapid. IMO the more interesting thing about chess skill at the top is how much way way better GMs are than everyone else. To me, ratings at the top feel more like an exponential scale than a linear one. For example, I have beaten International Masters at…
ELO ratings are constructed such that skill differences are invariant across the entire scale. A person who plays someone 200 ELO points lower is expected to win 76% of the time.
Re: When Grandmasters Blunder: Even the best make mistakes
#14Hi guys, author here. I'll be monitoring this thread for the rest of the evening. Happy to answer any questions.
« Assuming Anand and Carlsen’s blunders were independent events, what we saw was a 1 in 10,000 occurrence. » Are they independent events though? In a game between mediocre players, if there is only one move to take advantage of a blunder, the computer analysis will repeatedly cry "blunder!" each turn until either that move is played or the initial blunderer defuses the opportunity. As for grandmaster play, I have no…
My hypothesis would be that GMs are much less likely to blunder when there's a winning move on the board. They're generally very good at finding such moves.
Re: When Grandmasters Blunder: Even the best make mistakes
#15Grandmasters blunder more often than this. I would venture to say that what correlates with blunders more so than rating is time. Error rate goes way up in Blitz and Rapid. IMO the more interesting thing about chess skill at the top is how much way way better GMs are than everyone else. To me, ratings at the top feel more like an exponential scale than a linear one. For example, I have beaten International Masters at…
> Grandmasters blunder more often than this.
Could this analysis be a lower bound? I'm not familiar with Crafty, but given that all the games were annotated in 6 hours of wall-clock time, this analysis can't be going extremely deep into the game-tree. There may be many more moves which would qualify as blunders if analyzed as deeply as Regan's work in the other comment.
Re: When Grandmasters Blunder: Even the best make mistakes
#16It seems to me that the article overlooks one glaringly obvious issue: that the two blunders may not be independent events.
In this case, it seems quite likely that the second player's blunder was made much more likely by the fact that the first player had just blundered. To be more specific, white moved the king which appeared (at first glance) to prevent black from using a check threat to attack white's rook. The blunder was in not realizing that the check threat could still be used to attack white's rook, albeit in a more complicated fashion.
Black responded to this with another "blunder" -- failing to attack the rook and moving elsewhere instead. But this blunder was NOT independent of the first -- it is quite likely (I believe) that black saw the move and assumed white had successfully prevented the attack on the rook. He assumed that such a top-level player would never make such a mistake, and that caused him to not look closely enough at it. The first blunder helped cause the second.
(Thanks to stolio for linking to the game analysis I used here.)
One could test this hypothesis of mine using the same data set. Instead of looking just at single errors, look at error pairs (one error occurring in the move following another error). If the probability of a blunder is significantly higher on the move immediately after a blunder than it is at any other time, then my hypothesis (that the events are not independent, but correlated) is supported.
Re: When Grandmasters Blunder: Even the best make mistakes
#17Grandmasters blunder more often than this. I would venture to say that what correlates with blunders more so than rating is time. Error rate goes way up in Blitz and Rapid. IMO the more interesting thing about chess skill at the top is how much way way better GMs are than everyone else. To me, ratings at the top feel more like an exponential scale than a linear one. For example, I have beaten International Masters at…
Time definitely plays a huge roll in blunders. Actually if you look at the first graph there's a spike in blunders around 2800 which is entirely due to a single GM (Caruana) playing a string of blitz games this year in which he made several blunders.
Blitz games? Is your data from Blitz games played on an online server?
I like the idea of your research, but blitz games are garbage and online ratings are frequently meaningless due to abuse.
You should also look at replacing Crafty with Stockfish. Stockfish is still open source and it's around 350 points higher than Crafty which is a huge amount at this level.
Re: When Grandmasters Blunder: Even the best make mistakes
#18> Due to cost limitations we had to limit crafty to 2 seconds of analysis time per move
A grandmaster with standard time controls could defeat a 2-second limited Crafty. So how do you know you're finding true blunders, and not simply positions that the engine evaluates incorrectly?
Re: When Grandmasters Blunder: Even the best make mistakes
#19> Due to cost limitations we had to limit crafty to 2 seconds of analysis time per move A grandmaster with standard time controls could defeat a 2-second limited Crafty. So how do you know you're finding true blunders, and not simply positions that the engine evaluates incorrectly?
This is definitely the biggest limitation of our approach right now and there are certainly some things that we counted as blunders that aren't true blunders. We're working on rectifying this by doing another pass with a better engine and more time to analyze.
That said we tested this on a smaller set of games by comparing it to results from better engines and found that only a very small number of moves tricked crafty. It's still generally quite reliable for the majority of moves.
Re: When Grandmasters Blunder: Even the best make mistakes
#20Grandmasters blunder more often than this. I would venture to say that what correlates with blunders more so than rating is time. Error rate goes way up in Blitz and Rapid. IMO the more interesting thing about chess skill at the top is how much way way better GMs are than everyone else. To me, ratings at the top feel more like an exponential scale than a linear one. For example, I have beaten International Masters at…
>To me, ratings at the top feel more like an exponential scale than a linear one. For example, I have beaten International Masters at chess lots of times but have never once beaten a GM.
If true this is purely psychological. You are unable to beat a GM because he's a GM and you think you're unable to beat GMs.
The strength difference between IMs and GMs simply isn't that great. Because the GM title is based on results and not ratings there are frequently IMs who are higher rated than GMs.