Google explains how it ranks search results

Posted by Emma Woollacott

As the European Commission opens an anti-trust enquiry into Google, the company has revealed details of how it ranks its search results.

Amit Singhal, a Google Fellow responsible for ranking, says Google processes hundreds of millions of searches a day. More than one in five is a completely new query.

The company's algorithms, he says, are based on hundreds of criteria, from the words on a web page to the authoritativeness of other sites linking to it. They're in a state of constant flux, with, on average, one or two changes made every day.

Singhal defends the use of algorithms by saying that not only would it be impossible to handle queries by hand, but it wouldn't give the same level of quality.

"Every day we get the right answers for people, and every day we get stumped. And we love getting stumped. Because more often than not, a broken query is just a symptom of a potential improvement to be made to our ranking algorithm," he says.

"Improving the underlying algorithm not only improves that one query, it improves an entire class of queries, and often for all languages around the world in over 100 countries."

The EU is investigating three complaints against the company, one of which alleges that Google's search results are biased in favour of itself.

Singhal defends this by pointing to the results of searching for the term 'search engine'.

"In 0.14 seconds from among a few hundred million pages, our initial results are: AltaVista, Dogpile Web Search, Bing and Ask.com. I guess I'd better get back to work," he says.

The company hasn't tweaked the algorithm to deal with that one yet.