Why does the engine sometimes label what seems to be an obvious blunder as only an inaccuracy?

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erraticarchitect
After analyzing many games, I have noticed it is not uncommon for the engine to label a move that costs the game (usually in terms of material or position, not #) as an inaccuracy. Take for example this game I played against a friend of mine who just started playing chess.

Check out this #chess game: nate6837 vs erraticarchitect - https://www.chess.com/daily/game/496607243

He clearly blunders after taking with his knight, opening his hanging queen up to an absolute pin. But the engine does not agree with this, even though in the game review it even acknowledges that he is losing a queen this way.

Can anyone explain to me how the engine reaches these conclusions?
magipi
DrkNyx wrote:

Meaning that had the computer been playing, it would have calculated a combination to get out of that particular mess.

This is just complete nonsense. Please stop misleading people.

What really happens is that those labels ("inaccuracy" and "mistake" and "blunder") can't be trusted. Look at the real engine evaluation (switch to the "Analysis" tab), and look at that. Stockfish says that fxe4 is -5, while Nxe4 is -11. So yeah, a huge blunder.

Martin_Stahl
magipi wrote:
DrkNyx wrote:

Meaning that had the computer been playing, it would have calculated a combination to get out of that particular mess.

This is just complete nonsense. Please stop misleading people.

What really happens is that those labels ("inaccuracy" and "mistake" and "blunder") can't be trusted. Look at the real engine evaluation (switch to the "Analysis" tab), and look at that. Stockfish says that fxe4 is -5, while Nxe4 is -11. So yeah, a huge blunder.

-11 is completely losing for white and -4 is still completely losing. The site does not define that as a blunder.

Different people have different definitions for move classifications, though often blunders are defined as changing evaluations by two categories. So winning to even is likely considered a blunder but winning to a slight advantage is likely a mistake.

Not everyone is going to agree on a given definition and looking at the evaluation number, and given lines, is going to provide more context.

Cobra2721
magipi wrote:
DrkNyx wrote:

Meaning that had the computer been playing, it would have calculated a combination to get out of that particular mess.

This is just complete nonsense. Please stop misleading people.

What really happens is that those labels ("inaccuracy" and "mistake" and "blunder") can't be trusted. Look at the real engine evaluation (switch to the "Analysis" tab), and look at that. Stockfish says that fxe4 is -5, while Nxe4 is -11. So yeah, a huge blunder.

I agree

rgknapp4

I get this too. The game end screen says I had a blunder, but the Game Analysis screen shows 0 blunders.

It says "2 blunders"
it says "0" blunders for both of us.
ice_cream_cake

I was told by a friend that the different categories like blunder and mistake are based solely on the engine evals and not on the moves (someone correct me if I'm wrong) and as such, there must be an arbitrary choice made in determining the categories. Guess in some positions that are just hopeless anyway, making it worse may not be considered a blunder because there's nothing that would save the position anyway.