See our Review-aggregate webmaster docs for full explanation of the Review-aggregate type, and how to encode Review-aggregate data in RDFa, microformats or microdata. This page exists to contain a machine-readable microdata description of the Review-aggregate type itself (at the URI

An item with the item type represents a review of a business, product or organization. The following are the type’s defined property names:

Property Description
itemreviewed (item) The item being reviewed. In microformats, can contain the name of the item reviewed (fn).
rating A numerical quality rating for the item (for example, 4). You can indicate a rating scale by specifying best (default: 5) and worst (default: 1). More information about review ratings.
count The total number of reviews for the item.
votes Specifies the number of people who provided a rating with or without an accompanying review. A site can specify count or vote, or both.
summary A short summary of the collection of reviews that are being aggregated.