What are product reviews and how does Google treat them?

When someone talks about "product reviews" they can mean two different things, and it helps to know which before going further. One is a customer's opinion under the photo and price on your product page: four stars, a name, two sentences. The other is the write-up from someone who knows the product, like your store's guide comparing three models or a magazine article. Google has rules for both, but they are not the same rules, and mixing them up leads you to worry about the wrong thing.

What it includes

Your customers' reviews

The reviews buyers leave are UGC, content created by users rather than the store. Google is explicit on one point: its reviews system does not evaluate third-party reviews, such as the ones users post in the reviews section of a product or service page.⁠^{[1]Google Search Central. Google Search's reviews system and your website} That does not make them invisible to Google. They reach it two ways.

The first is the page's own markup. Each review can be described as a Review node and the average as an AggregateRating, and with that the page can qualify for stars in Google's rich results. The content rules weigh more than the code: marked-up reviews have to be visible on the page, you may not gather reviews or ratings from other sites, and fake reviews and incentivized reviews without disclosure stay out, both from the page and from the markup. Google also recommends accepting only ratings that come with a comment and the author's name.⁠^{[2]Google Search Central. Review snippet (Review, AggregateRating) structured data} The properties, one by one, are in the Review entry.

The second is Google Merchant Center. Its product ratings program shows stars on Shopping ads and free listings, and asks for a minimum of 50 reviews across all your products combined. They are sent through a supported review aggregator or with your own reviews data feed, which has to be uploaded at least once a month with up-to-date reviews. It is available in the countries where Shopping ads and free listings exist.⁠^{[3]Google Merchant Center Help. Product Ratings eligibility} The same reviews, then, can reach Google twice: in the page's code and in Merchant Center's reviews feed.

The write-ups you publish

Google's reviews system aims to reward high-quality reviews: write-ups with insightful analysis and original research, written by experts or enthusiasts who know the topic well.⁠^{[4]Google Search Central. A guide to Google Search ranking systems} It applies to first-party content published as a standalone piece: the review of a single product, a comparison between two, or a ranked list of recommendations. It works mostly page by page, though on sites with a lot of review content it can evaluate any page of the site. It works in several languages, Spanish among them, and Google improves it continuously without announcing each change.⁠^{[1]Google Search Central. Google Search's reviews system and your website}

Its guide to writing reviews lists among possible authors a merchant who guides people between competing products, that is, a store with buying guides. What it recommends: show evidence of your own experience, such as photos, audio or other links; give measurements of how the product performs in each aspect; explain what sets it apart from the competition; cover comparable alternatives or say which one suits each use; and discuss pros and cons from original research. It also suggests linking to several sellers so the reader can choose where to buy.⁠^{[5]Google Search Central. Write high quality reviews}

In a store

A made-up example: a photography gear store and the four pieces on its site that someone might call "reviews".

The third row is the one most stores overlook. A buying guide with photos taken by the team, the measured weight of each tripod and a clear recommendation by type of trip is exactly what Google's guide describes; a list of product pages with the manufacturer's description is not.

How to check it

1. Count the reviews a customer sees on a product page and compare them with the ones in the code: the same author, the same rating, the same text.⁠^{[2]Google Search Central. Review snippet (Review, AggregateRating) structured data}
2. Confirm where they come from. They have to have been written on your site, not gathered from others.⁠^{[2]Google Search Central. Review snippet (Review, AggregateRating) structured data}
3. Review what you promise about them. If you say they are from buyers, write down what check you use to verify it.
4. If you have at least 50 reviews in total, look in Merchant Center to see whether your store meets the product ratings requirements and how often the feed is updated.⁠^{[3]Google Merchant Center Help. Product Ratings eligibility}
5. Read your buying guides with Google's list in hand: original evidence, measurements, what sets each product apart, and pros and cons.⁠^{[5]Google Search Central. Write high quality reviews}

Related concept: Review

Product reviews are what a person writes; Review is the way of describing each one for machines, a Schema.org type with author, rating and text, and AggregateRating is the average of all of them. A store can have reviews without markup, and then Google does not have a description of each one in the code; what it cannot have is markup without visible reviews, because Google's rules ask that what is marked up be on view.⁠^{[2]Google Search Central. Review snippet (Review, AggregateRating) structured data} The Review entry explains the properties and the AggregateRating one, the average.

To go further, the catalog and entities reading path orders the rest of the product page terms.