Imagine you are 1900 Elo. You are paired against a 1500 Elo junior. You play carefully, equalize after every complication, and split the point.

Over the board it feels like a “correct” draw against an equal practical opponent. On the rating sheet it is a penalty of -8.4 Elo points.

You did not blunder, but your number still drops.
This is no longer rare noise. It is the new normal.

🧵1/8 The Elo formula sees a 400-point gap and expects you (the 1900 Elo player) to score 92 %.

Reality: the players are equal strength and draw → 50 %.

You perform according to your real strength, but lose 8.4 rating points because you failed to meet the formula’s expectation.

That gap between expected score and actual score is the adjustment cost. Repeat it across many games and the pressure concentrates on rating favorites.

🧵2/8