All about the new Google RankBrain algorithm

Recently, news emerged that Google was using a machine-learning artificial intelligence system called “RankBrain” to help sort through its search results. Wondering how that works and fits in with Google’s overall ranking system? Here’s what we know about RankBrain.

The information covered below comes from three original sources and has been updated over time, with notes where updates have happened. Here are those sources:

First is the Bloomberg story that broke the news about RankBrain yesterday (See also our write-up of it). Second, additional information that Google has now provided directly to Search Engine Land. Third, our own knowledge and best assumptions in places where Google isn’t providing answers. We’ll make clear where these sources are used, when deemed necessary, apart from general background information.

What is RankBrain?

RankBrain is a machine learning artificial intelligence system, the use of which by Google was confirmed on 26 October 2015. It helps Google to process search results and provide more relevant search results for users.

What is machine learning?

Machine learning is where a computer teaches itself how to do something, rather than being taught by humans or following detailed programming.

What is artificial intelligence?

True artificial intelligence, or AI for short, is where a computer can be as smart as a human being, at least in the sense of acquiring knowledge both from being taught and from building on what it knows and making new connections.

True AI exists only in science fiction novels, of course. In practice, AI is used to refer to computer systems that are designed to learn and make connections.

How’s AI different from machine learning? In terms of RankBrain, it seems to us they’re fairly synonymous. You may hear them both used interchangeably, or you may hear machine learning used to describe the type of artificial intelligence approach being employed.

So RankBrain is the new way Google ranks search results?

No. RankBrain is part of Google’s overall search “algorithm,” a computer program that’s used to sort through the billions of pages it knows about and find the ones deemed most relevant for particular queries.

So RankBrain is part of Google’s Hummingbird search algorithm?

That’s our understanding. Hummingbird is the overall search algorithm, just like a car has an overall engine in it. The engine itself may be made up of various parts, such as an oil filter, a fuel pump, a radiator and so on. In the same way, Hummingbird encompasses various parts, with RankBrain being one of the newest.

In particular, we know RankBrain is part of the overall Hummingbird algorithm because the Bloomberg article makes clear that RankBrain doesn’t handle all searches, as only the overall algorithm would.

Hummingbird also contains other parts with names familiar to those in the SEO space, such as Panda, Penguin and Payday designed to fight spam, Pigeon designed to improve local results, Top Heavy designed to demote ad-heavy pages, Mobile Friendly designed to reward mobile-friendly pages and Pirate designed to fight copyright infringement.

RankBrain is the third-most important signal?

That’s right. From out of nowhere, this new system has become what Google says is the third-most important factor for ranking webpages. From the Bloomberg article:RankBrain is one of the “hundreds” of signals that go into an algorithm that determines what results appear on a Google search page and where they are ranked, Corrado said. In the few months it has been deployed, RankBrain has become the third-most important signal contributing to the result of a search query, he said.

What exactly does RankBrain do?

Used as a way to interpret the searches that people submit to find pages that might not have the exact words that were searched for.

Didn’t Google already have ways to find pages beyond the exact query entered?

Yes, Google has found pages beyond the exact terms someone enters for a very long time. For example, years and years ago, if you’d entered something like “shoe,” Google might not have found pages that said “shoes,” because those are technically two different words. But “stemming” allowed Google to get smarter, to understand that shoes is a variation of shoe, just like “running” is a variation of “run.”

Google also got synonym smarts, so that if you searched for “sneakers,” it might understand that you also meant “running shoes.” It even gained some conceptual smarts, to understand that there are pages about “Apple” the technology company versus “apple” the fruit.

How’s RankBrain helping refine queries?

The methods Google already uses to refine queries generally all flow back to some human being somewhere doing work, either having created stemming lists or synonym lists or making database connections between things. Sure, there’s some automation involved. But largely, it depends on human work.

The problem is that Google processes three billion searches per day. In 2007, Google said that 20 percent to 25 percent of those queries had never been seen before. In 2013, it brought that number down to 15 percent, which was used again in yesterday’s Bloomberg article and which Google reconfirmed to us. But 15 percent of three billion is still a huge number of queries never entered by any human searcher - 450 million per day.

Among those can be complex, multi-word queries, also called “long-tail” queries. RankBrain is designed to help better interpret those queries and effectively translate them, behind the scenes in a way, to find the best pages for the searcher.

As Google told us, it can see patterns between seemingly unconnected complex searches to understand how they’re actually similar to each other. This learning, in turn, allows it to better understand future complex searches and whether they’re related to particular topics. Most important, from what Google told us, it can then associate these groups of searches with results that it thinks searchers will like the most.

Google didn’t provide examples of groups of searches or give details on how RankBrain guesses at what are the best pages. But the latter is probably because if it can translate an ambiguous search into something more specific, it can then bring back better answers.

Does RankBrain really help?

Despite my two examples above being less than compelling as testimony to the greatness of RankBrain, I really do believe that it probably is making a big impact, as Google is claiming. The company is fairly conservative with what goes into its ranking algorithm. It does small tests all the time. But it only launches big changes when it has a great degree of confidence.

Integrating RankBrain, to the degree that it’s supposedly the third-most important signal, is a huge change. It’s not one that I think Google would do unless it really believed it was helping.

When Did RankBrain start?

Google told us that there was a gradual rollout of RankBrain in early 2015 and that it’s been fully live and global for a few months now.

What queries are impacted?

In October 2015, Google told Bloomberg that a “very large fraction” of the 15 percent of queries it normally never sees before were processed by RankBrain. In short, 15 percent or less.

In June 2016, news emerged that RankBrain was being used for every query that Google handles.

NOTE: This story has been revised from when it was originally published in October 2015 to reflect the latest information.(Here on Blog its published for reference only)