The public score is the arithmetic mean of all eligible published reviews, rounded half-up to one decimal.
Use reviews with state published and score_eligible = 1.
Add current overall ratings and divide by eligible count.
Round half-up to one decimal; no reviews means no score, never 0.0.
The headline uses all eligible reviews.
A secondary aggregate shows recent movement.
Event cache must exactly match a complete rebuild.
YouReview always shows count, formula version and source labels.