April 12, 2013
Results Change Over Time as Algorithms Determine Relevance
Your new site or page might rank well initially but, after a week, it begins to drop, declining over time to a middle-of-the-pack slot. Why?
Matt Cutts, head of Google’s Webspam team, recently put together a video to explain the phenomenon.
Cutts said Google’s algorithms can, initially, have a hard time figuring out the original source of new content. Time changes that, however.
“Writing a search engine is kind of a complex task,” Cutts said. “You’re trying to make sure you return the best quality result but you also have to do that with limited information.”
Cutts likened the ranking process to the reporting of breaking news during an earthquake.
For instance, he said, one minute after an earthquake occurs there is limited information about what happened, ten minutes later there is slightly more information and an hour later a lot more information.
“With any event that has breaking news, it can be hard to know (what is accurate) even if multiple people are saying the same thing,” he said. “One person might be the original author another person might be using an RSS” feed to relay information.
“It can be difficult to try to suss out … where this content was appearing originally. And, over time, over the course of hours, days or weeks, that gets easier. But it can be hard after just minutes or hours.”
Cutts said initial rankings are often Google’s “best guess” on how relevant a page or piece of content is.
As more information becomes available, Google incorporates its new knowledge into the mix and, “typically, things settle down into a steady state,” Cutts said. “When there is a steady state, we’re better able to guess how relevant something is.”
Armed with that information, Google can then determine if the page or content would be better served by QDF (queries that deserve freshness) or evergreen.
QDF is a component of the Google algorithm for queries that need frequent updating, such as breaking news stories.
If Google determines the best results for a particular search will change daily, or even hourly, it will designate the search QDF. Such designations means new and relevant content will make its way to the top of the search results. It also means, however, that content will quickly be bumped as newer relevant content is posted.
Evergreen, on the other hand, is a term Google applies to pages or sites that are frequently updated and are likely to attract both first-time and repeat visitors.
“A lot of people think there should be one set of rankings, it should be completely uniform, everybody in the world should see the exact same thing,” Cutts said. “The fact is, we have different results for people in different countries, even in different cities.
“And the results can change over time. Not just because links change or the content on the page changes, but because we are better able to assess which pages are more relevant.”