Google uses a multitude of factors to determine how to rank search engine results. Typically, these factors are either related to the content of a webpage itself (the text, its URL, the titles and headers, etc.) or were measurements of the authenticity of the website itself (age of the domain name, number and quality of inbound links, etc.). However, in 2010, Google did something very different. Google announced website speed would begin having an impact on search ranking. Now, the speed at which someone could view the content from a search result would be a factor.
Unfortunately, the exact definition of “site speed” remained open to speculation. The mystery widened further in June, when Google’s Matt Cutts announced that slow-performing mobile sites would soon be penalized in search rankings as well.
Clearly Google is increasingly acting upon what is intuitively obvious: A poor performing website results in a poor user experience, and sites with poor user experiences deserve less promotion in search results. But what is Google measuring? And how does that play into search engine rankings? Matt Peters, data scientist at Moz, asked Zoompf to help find the answers.
While Google has been intentionally unclear in which particular aspect of page speed impacts search ranking, they have been quite clear in stating that content relevancy remains king. So, in other words, while we can demonstrate a correlation (or lack thereof) between particular speed metrics and search ranking, we can never outright prove a causality relationship, since other unmeasurable factors are still at play. Still, in large enough scale, we make the assumption that any discovered correlations are a “probable influence” on search ranking and thus worthy of consideration.
The back-end performance of a website directly impacts search engine ranking. The back end includes the web servers, their network connections, the use of CDNs, and the back-end application and database servers. Website owners should explore ways to improve their TTFB. This includes using CDNs, optimizing your application code, optimizing database queries, and ensuring you have fast and responsive web servers. Start by measuring your TTFB with a tool like WebPageTest, as well as the TTFB of your competitors, to see how you need to improve.
While we have found that front-end web performance factors (“document complete” and “fully rendered” times) do not directly factor into search engine rankings, it would be a mistake to assume they are not important or that they don’t effect search engine rankings in another way. At its core, front-end performance is focused on creating a fast, responsive, enjoyable user experience. There is literally a decade of research from usability experts and analysts on how web performance affects user experience. Fast websites have more visitors, who visit more pages, for longer period of times, who come back more often, and are more likely to purchase products or click ads. In short, faster websites make users happy, and happy users promote your website through linking and sharing. All of these things contribute to improving search engine rankings. If you’d like to see what specific front-end web performance problems you have, Zoompf’s free web performance report is a great place to start.
Our data shows there is no correlation between “page load time” (either document complete or fully rendered) and ranking on Google’s search results page. This is true not only for generic searches (one or two keywords) but also for “long tail” searches (4 or 5 keywords) as well. We did not see websites with faster page load times ranking higher than websites with slower page load times in any consistent fashion. If Page Load Time is a factor in search engine rankings, it is being lost in the noise of other factors. We had hoped to see some correlation especially for generic one- or two-word queries. Our belief was that the high competition for generic searches would make smaller factors like page speed stand out more. This was not the case.
As we have seen, back-end performance and TTFB directly correlate to search engine ranking. Front-end performance and metrics like “document loaded” and “fully rendered” show no correlation with search engine rank. It is possible that the effects are too small to detect relative to all the other ranking factors. However, as we have explained, front-end performance directly impacts the user experience, and a good user experience facilitates the type of linking and sharing behavior which does improve search engine rankings. If you care about your search engine rankings, and the experience of your users, you should be improving both the front-end and back-end performance of your website. In our next blog post, we will discuss simple ways to optimize the performance of both the front and back ends of a website.