aggregateRating

AggregateRating is a schema.org type used to describe the average rating of an item based on multiple ratings or reviews. It provides a compact summary of public opinion about an item such as a product, movie, book, or event. The aggregateRating is usually posted as a property of the item (aggregateRating) in structured data, enabling search engines and other services to display star ratings or other visual summaries in search results.

Common properties:

- ratingValue: the average rating expressed as a number.

- ratingCount: the number of individual ratings that contributed to ratingValue.

- reviewCount: the number of reviews that contributed to ratingValue, and may differ from ratingCount if some reviews do not include a rating.

- bestRating and worstRating: define the scale’s upper and lower bounds; defaults may be 5 and 1 if omitted.

- ratingExplanation: optional text explaining the basis of the aggregate rating.

Usage notes: The aggregate rating should reflect only verifiable, representative input; do not inflate with fake or duplicate ratings. When presenting, ensure that the ratingValue, ratingCount, and reviewCount are consistent and up-to-date. The type is distinct from individual Reviews or Ratings, which express single opinions; AggregateRating aggregates many.

See also: Rating, Review, Schema.org, Rich results.