When we choose which opening moves to play, many of us take opening statistics seriously into consideration, often more so than computer evaluations o

Why Opening Statistics Are Wrong

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Style Pass

2024-10-01 14:30:06

When we choose which opening moves to play, many of us take opening statistics seriously into consideration, often more so than computer evaluations or master-level theory. This is reasonable: a +0.8 advantage on move 5 matters little when every other move in the middlegame is a blunder. Computer and master moves may be the best in theory, but are not necessarily the ones that provide the best practical chances for amateur blitz players.

So, we dive into the opening explorer, choose our rating range and look for moves that offer a high win rate at our level. This is not the only criterion of course (simplicity and soundness matter a lot to me), but it is an important one. Whether an amateur should even bother with all that is a different question but whatever floats our boats.

The problem with opening statistics is that they are wrong. By “wrong”, I do not mean of course that there is some error in the code that calculates them. I mean that the methodology of grouping by *average* rating is flawed. If you are a 2100-rated player and choose the “2000-2200” category in the opening explorer, you want to see how people with your rating perform when they play different openings. Instead, you get a substantially distorted picture of that. That is because you get the statistics on games where the *average* rating of the two players is in the [2000,2200) range (greater or equal to 2000, smaller than 2200).