Why your BAR rating drops after a win

OpenSkill, the rating system BAR uses, measures your skill position on a probability curve. When your uncertainty shrinks, the numbers can move in surprising directions, including downward after a victory.

Tags: beyond all reason, BAR rating drops, BAR OpenSkill, BAR MMR, why did my rating go down

Two numbers: mu and sigma

OpenSkill tracks two values. Mu represents where the system thinks your skill level sits. Sigma represents how uncertain the system is about that estimate. Your visible rating combines both numbers. As you play more matches, sigma decreases because the system gains confidence in your placement.

How wins can lower your visible rating

When you start with high uncertainty, your displayed rating is inflated. Each match tightens the range. If sigma drops faster than mu increases from a win, your visible rating goes down even though you won. This is normal and means the system is converging on your actual skill level.

Season resets make this more visible

At the start of each season, sigma increases and mu resets toward a default value. Your displayed rating drops for everyone. The first few matches of a new season will feel more volatile as the system re-establishes where you belong on the curve.

Rating should not be your only metric

Focus on decision quality, economy management, and army composition. The rating number is a side effect of improving at those fundamentals. If your rating fluctuates while your actual play gets better, trust the play. The rating catches up eventually.