Why does Google customize some search results based on previous related queries that you’ve performed? Is there a special relationship between those query terms, and if so, how did Google define that relationship? This is not from some third-party company. It is something that Google is doing – deciding that some queries are related queries.

Imagine searching for a “luxury car” at Google and then performing another search for “Infiniti.” On the second search, you find a page in the search results that looks like it will provide you with information that you are looking for, and you select a page.

Now imagine that many other people perform the same series of searches and select the same page.

Google might start considering the search for “luxury car” and the search for “Infiniti” as related queries. It’s also possible that the page selected in the second search for “Infiniti” might start ranking more highly for the query “luxury car.

A patent filed by Google in 2003 got granted this week, and it explores how search rankings might be “improved” by looking at related queries. Google appears to be learning by watching searches and paying attention to related queries.

Methods and systems for improving a search ranking using related queries Invented by Simon Tong, Mark Pearson, and Sergey Brin Assigned to Google US Patent 7,505,964 Granted March 17, 2009 Filed: September 12, 2003

The patent tells us that Google might use many different approaches to determining whether queries might become related and uses an example of queries performed back-to-back or consecutively as one of those approaches. Besides tracking which queries a searcher might perform, the patent tells us that it might track the behavior of searchers, such as which pages a searcher might click through in a set of search results:

For example, when a user types in a first search query such as “infinity auto” and then inputs a second search query such as “Infiniti” immediately afterward, the related query processor may define a relationship between the first search query and the second search query.

In this example, the relationship of proximity between search queries would become defined as “back-to-back” or consecutive.

Thus, for the query “infinity auto,” relationships to queries “Infiniti,” “luxury car,” “quality luxury car,” and “Japanese quality luxury car” may get defined if a user inputs these queries immediately following the initial query “infinity auto.” It would consider those to be related queries.

Other types of relationships or proximities can get defined according to the invention and stored by the related query database.

Relationships between queries might get determined and weighed differently based upon a few different considerations.

Weighting Relationships Between Queries

For instance, queries might be more closely related if they are typed in by a searcher consecutively than if there are one or more queries between them.

Or queries might be determined to be related if they are performed by a searcher with a certain period of time, such as within 30 minutes of one another. The patent provides many examples of how queries might get related, which include:

  • Having been input as consecutive search queries by users previously (whether once or multiple times),
  • Queries input by a user within a defined time range (e.g., 30 minutes),
  • Misspellings
  • Numerical relationships
  • Mathematical relationships
  • Translation relationships

If you’ve performed a few searches on Google, you may have noticed a message at the top left of the search results that tell you that your results are “Customized based on recent search activity.” Following a “More Details” link next to that statement might tell you which the previous query influenced the results you see. When I followed an example from the patent and searched for “infinity auto,” and then followed it up with a search for “Infiniti,” I received a message that”

The following information has gotten used to improve your search results for Infiniti:

Recent Searches You or someone else recently searched for infinity auto using this browser.

A “learn more” link from that message told me that:

Recent searches: We consider whether a particular query followed on the heels of another query. Because recent search activity provides valuable context for understanding the meaning behind your searches, we use it to customize your results whenever possible, regardless of whether you’re signed in or signed out.

To customize your results and show you the customization details, we keep recent searches in a cookie on your browser for approximately 30 minutes. After approximately 30 minutes, this cookie can get removed from your browser. Completely closing your browser will remove this cookie immediately.

– Features: Search customization details

We don’t know for certain if this patent provides us with details of how this “related query” process works at present. It’s been more than five years since the patent was originally filed. But, it is interesting to think about how queries might become related. Or how those relationships might influence the search results that you might see when you perform a search.