Does page load time affect Google rankings?

Google is constantly refining and extending how it ranks pages in search results. Often the  changes are about content but increasingly more technical and experiential factors are influencing results. But does page load time affect Google rankings – and therefore impact your chances of getting found?

How does Google use Site Speed data?

There has been much speculation around whether page load time affects Google rankings. A site speed module has long been a page of Google Webmaster tools and the things that Google betas here are usually a clue to what they’re thinking. Google’s Matt Cutts also announced that site speed would begin to be a factor in ranking results.

Is there any real evidence, though, that page load time is being used to influence rankings? Moz.com recently published the results of a study to determine just that.

4 key aspects of site speed

The study looked at 40 different metrics but focussed in on four key aspects of page load time. They looked at the top 50 results for 2,000 short and long search queries. Consequently, the following factors were investigated for 100,000 pages included in Google search engine results pages (SERPS):

• Page load time – the Moz study looked at both the time taken to fully render a page and the time before the user is able to use the page
• Time to first byte – the time it takes for your browser to receive the first data from your site
• Page size – the total amount of data downloaded to completely render the page including images, html, JavaScript, widgets, tracking code etc
• Total image content – the combined size of all images on the page

The Joy of SEO

Perhaps surprisingly, the study found that only Time To First Byte (TTFB) seemed to have a direct effect on  ranking. The correlation was flat for the other key metrics – apart from Page Size where the larger pages ranked better. So the answer was that page load time didn’t have an effect rankings.

The joy of SEO (that’s a book in itself) is that we don’t know exactly which do factors influence ranking or how they inter-relate. The assumption is that larger pages tend to rank higher is a side-effect rather than part of the Google Algorithm. The fact is that many of the most popular sites – with higher numbers of in-links and higher click-through rates – also tend to be more extensively designed with more page assets.

Pay attention to TTFB

Achieving an optimal TTFB is a result of back-end performance rather than anything in our on-page optimisation. It’s the result of things like server optimisation, application/code performance, use of content delivery networks, your CMS system etc. Google is presumably working on the principle that users don’t like to wait and boosting the rankings for sites that respond quickly.