There are several ways to add aggregate ratings — as I’ll explain below — but first, before we dive into the “How”, let’s talk about what an “aggregate rating” actually is. ;-) The Schema.org website defines the Schema aggregateRating property value as:
The overall rating, based on a collection of reviews or ratings, of the item.
Two things to keep in mind about this:
- An aggregate rating value is calculated from several customer ratings / reviews for the current webpage content (an e-commerce product review, for example).
- Google prefers — and often double-checks — that Schema markup reflects the current content of the webpage. So, if you want to manually set aggregate rating and/or review values in your Schema markup, make sure that these customer ratings and/or reviews also appear in your webpage content (ie. the ratings and reviews are visible).