Fishy stockfish

Somehow, I did the blunder (18. ... ♝g7?) but why do the stockfish analyzer say my opponent recorded the blunder with the little bad move (16. ♘xb5?? ...)?

@AdityaMH #1
Difference is that after your move you were still winning (+4 vs. +9), while your opponent could make a winning move 16.Bxb5 but instead dropped the winning advantage into a "white is better" 16.Nxb5.

I think the inaccuracy/mistake/blunder classification is based on percentage of advantage lost rather than the absolute value. So if eval goes from +3 to +1 it would be a blunder, whereas +10 to +8 would not even be considered an inaccuracy.

p.s. there is a possibility that the classification function may take into account both the percentage delta and absolute value delta, I'm not 100% sure. My point is that percentage advantage shift is certainly a big factor.

But my negative points much higher than him at that moment.

P. S.: positive points is for white winning point and negative points is for black winning point.

#3 is correct, Inaccuracy/Mistake/Blunder is decided based on changes in winning chances, a percentage.

This function shows how Stockfish evaluation relates to winning chances:

lichess.cdn.prismic.io/lichess/d98444c471c2af7bf073fa90f428998fb73706a2_learn-wc.png

As you can see, the difference between +4 to +1 is much bigger than the difference between +4 to +9.