Meaning of colours and percentages
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Could someone explain to me the meaning of the percentages and black and white colours that appear in the openings book of this App? Thank you so much in advance!
It represents the percentage of black winning in that position, white winning and a percentage of a draw.
Ok! Thank you very much!
You're welcome.
I thought this too at first but this seems to be wrong: For example after 1.e4 b5 there are three games in the database (33% draw and 67% win for black) but if you go another move deeper there is a win with white (with 2.d3) and many more games (about 450) instead of the original three games after 1.e4 b5.
What am I missing here?
Those 450 games were a certain position, which could be reached by several different move orders. You were looking at a rare position that a few people transposed back to more common position.
Keep in mind, when an author says something like "The Najdorf Sicilian scores 47% for Black", that does not mean Black wins 47% of the time. It is total points divided by total games.
You can figure out the percentage for Black by taking the percentage of Black wins plus half the percentage of draws.
So let's say you see the numbers 36, 34, and 30.
36 + (0.5*34) = 53 = Percent score for White
30 + (0.5*34) = 47 = Percent Score for Black
Okay so I think ThrillerFan is talking about the thing I don't get. But when you/he says: "it is total points divided by total games" I have no idea what points this is about.
TarLPa wrote:
Okay so I think ThrillerFan is talking about the thing I don't get. But when you/he says: "it is total points divided by total games" I have no idea what points this is about.
Have you never played in a chess tournament?
A win is 1 point
A draw is 1/2 of a point.
So if you take 1000 GM games with the French Poisoned Pawn variation. Let's say White win 365 of them. Let's say Black won 287 of them. That would mean 348 of them were drawn (numbers are fictitious and only to illustrate the concept).
The WRONG way to figure it is to say Black scores 28.7%. That is simply how often he WINS! That is actually a good score for Black wins.
To figure out Black's percentage, you have to figure it out based on points scored divided by total games.
287 wins is 287 points
348 draws is 174 points (1/2 point for each draw)
287 + 174 = 461 points scored in 1000 games.
Therefore, in this hypothetical example, Black scores 46.1%.
If you were to figure out White's score, it would be 539/1000, or 53.9%
White's percentage and Black's percentage will always add up to 100%.
Another way to think of it is as follows:
In 1000 games, Black had the opportunity to score 1000 points. Of those 1000 available points, he scored 461 of them, and 461 points out of a possible 1000 is 46.1%.
If you want to see an easier example, look at the tournament I played in this weekend. Here were my results:
Round 1 - White - 1-0
Round 2 - Black - 1/2-1/2
Round 3 - White - 1-0
Round 4 - Black - 1/2-1/2
Round 5 - White - 1-0
So that is 3 wins and 2 draws in 5 games. People that do not understand percentages would say I scored 60% (3 wins in 5 games). This again would be wrong!
I got 3 wins, worth 3 points, and 2 draws, with 1 point (half a point each).
That is 4 out of 5 (hence why my tournament score was 4), and 4/5 is 80%, and so I scored 80% this past weekend.
Again, that is how percentages work, for a player or for a color (when talking opening statistics).
In that tournament, the French Defense was played in 3 games (1, 2, and 4). White won the first and the other 2 were drawn.
Black did not win a single game, yet he scored 33% (1 point out of a possible 3) with the French.
Now obviously 3 games is too small of a sample size, and so that is why statistics are based on all games of a certain opening over the course of a certain time frame, like you might want to know how the French has scored in the last 20 years, so you search your database for C00-C19 and 2002-2021, then calculate based on White points scored and Black points scored divided by total games in that time period.