Google’s Gary Illyes explains a case where a word that means the opposite may be treated as a low weight synonym when returning search results.
The example he discusses is a search for “buy cars” in which the word “sell” would be considered a synonym.
“Buy” and “sell” are antonyms — so why would Google return pages about selling cars when a user is looking for information about buying one?
To answer that question let’s dive into the conversation between Illyes and Google’s John Mueller, which takes place in episode 19 of the Search Off the Record podcast.
The episode focuses on information retrieval and how Google parses queries to return search results. Their discussion delves into synonyms and how a term like “purchase auto” is a low weight signal for the term “buy car.”
Mueller then asks the following question:
“One of the things I noticed, you were talking about “buy cars” and “buy automobiles” and all of these things, would we also consider “sell” a synonym to “buy”?
In the sense, like if I’m searching “to buy a car,” would we say, well, we’re looking for pages that say “sell car“?”
Sometimes Mueller even has to ask questions about search. Here’s the response from Illyes.
Antonyms As Low Weight Synonyms
Illyes responds with a definitive yes. Google will, in fact, look for pages that mention “sell car” when a user is searching for “buy car.”
He clarifies that “sell” is a lower weight signal than “buy,” but it’s still considered relevant to the user’s query.
“Yes. You are touching on a topic that’s very interesting from information retrieval perspective… But yes, we would consider that a low weight synonym. So “buy” and “sell” from information retrieval perspective is kind of synonyms, which can also cause confusions of course. Hence, why the weighting was introduced.”
Mueller follows up by asking if this is something site owners should take into consideration when writing content.
Using the same example — if a site owner is creating a page about selling cars should they try to mention the term “buy car”?
Illyes advises against that strategy, saying to keep the content focused on the target audience and what you want them to do after reading the copy.
“I don’t think so, because if you are just creating a site for the user and you are loading the page with content that is relevant for what the user can do on that page, like purchase a car, for example, then you wouldn’t want to overload that page with the term “sell” because your primary target is to make the user buy through your website a car, right?
And then there’s a subsection of users who would want to also sell their car. But they are not your target audience. Your target is to make the user buy a car.
… And as far as I remember from my marketing classes from uni is that you have to– well, actually, not marketing but writing classes– is to tell the person reading the content what you want from them…”
This is a good example of the difference between writing for users versus writing for search engines.
Google may return pages that mention “sell cars” when a user is looking for “buy cars,” but that doesn’t mean you should write a page optimizing for both terms.
Think like a marketer and keep the page focused on the action you want users to take after reading the content.
For more technical details about Google’s information retrieval process, listen to the full podcast episode.