About review data
When review information is marked up in the body of a web page, Google can identify it and may make it available in search results pages. Review information such as ratings and descriptions can help users to better identify pages with good content.
Wondering how your site might be listed in search results? Check out the Rich Snippets testing tool.
Properties
Google recognizes the following Review properties. Where the RDFa Review and microformats hReview property names differ, the hReview property appears in parentheses.
| Property | Description |
itemreviewed (item) | The item being reviewed |
name (fn) | The name of the item being reviewed. Child of item. |
rating | A numerical quality rating for the item (for example, 4) based on a scale of 1-5. You can optionally specify worst (default: 1) or best (default: 5) |
reviewer | The author of the review. |
dtreviewed | The date that the item was reviewed. |
description | The body of the review. |
summary | A short summary of the review. |
Note: For simplicity, examples are shown with only the information that is being tagged. However, in realistic pages, these tags will be spread throughout the web page, mixed with unmarked text. It's important that the content is marked up where it actually appears on the page. It may seem more efficient to add all relevant content for rich snippets in a single block of text, and hide this text using CSS or other techniques, but except in special circumstances (for example when marking the best possible rating for review sites that don't use a 5-point rating scale), Google will not display content from hidden text.
Example: Microformat
<div class="hreview">
<span class="item">
<span class="fn">L'Amourita Pizza</span>
</span>
<span class="rating">3.5</span>
<span class="reviewer">Ulysses Grant</span>
<span class="dtreviewed">2009-01-06</span>
<span class="summary">"Delicious, tasty pizza in Eastlake."</span>
</div>
The structured information is conveyed by the class properties (such as class="rating" and class="reviewer", and the values (such as 3.5, Ulysses Grant), etc. You can change the tags such as span and div to suit your formatting needs.
Note:Sometimes the rating is included directly in the HTML, but in other cases webmasters often use an image to indicate a rating (for example, an image showing four stars out of five). If your site uses an image to indicate a rating, you should add class="rating" to the image tag. Google will extract the rating from the alt text. For example:
<img class="rating" src="star_rating_sprites.gif" alt="4 Star Rating: Recommended" />
Example: RDFa
<span xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Review"> <span property="v:itemreviewed">Komala Vilas</span> <span property="v:reviewer">Meenakshi Ammal</span> <span property="v:rating">3.7</span> <span property="v:dtreviewed">1st April 2005</span> <span property="v:summary">Best south Indian vegetarian food in South Bay</span> </span>
Aggregated reviews
Google also recognizes markup about aggregated reviews (for example, the total number of reviews, or the average rating). For example, a restaurant may have 45 reviews, with an average rating of 4.5. Aggregating reviews allows you to convey this information.
Google recognizes the following Review-aggregate properties. Where the RDFa Review-aggregate and microformats hReview-aggregate property names differ, the hReview-aggregate property appears in parentheses.
| Property | Description |
itemreviewed (item) | The item being reviewed |
name (fn) | The name of the item being reviewed. Child of item. |
rating | Container for rating information. |
average | The average rating of all reviews. Child of rating. |
count | The total number of reviews for the object |
summary | A short summary of the collection of reviews that are being aggregated. |
Example: Microformats
<div class="hreview-aggregate">
<div class="item">
<span class="fn">L'Amourita Pizza</span>
</div>
<div class="rating">
<span class="average">4.4</span>
</div>
<span class="count">1,313</span>
</div>
Example: RDFa
<span xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Review-aggregate">
<span property="v:itemreviewed">Komala Vilas</span>
<span rel="v:rating">
<span property="v:average">3.6</span>
</span>
<span property="v:count">20</span>
</span>