18 Questions (and Answers) About Google, Site Speed, and SEO

Last month, Google announced that, coming soon, pages that load slowly on mobile devices will be penalized in mobile search. This has led to widespread speculation about how Google will factor mobile performance into its search ranking algorithm. Today, I’m going to address this issue, as well as answer a handful of frequently asked questions about site speed and SEO, including:

  • How does Google actually calculate page speed in its ranking algorithm?
  • What can I do to make my pages faster for SEO purposes?
  • How much does site speed really matter when it comes to SEO?

1. Does the Google search bot track load time?

A lot of people assume that Googlebot measures page load, but no, the bot has nothing to do with measuring speed.

2. Does Google use its PageSpeed tool to measure page speed for the purposes of search ranking?

This is an understandably confusing question for many people, because PageSpeed is the name of the Google tool used to look at a page’s performance. To clarify, the speed at which a site loads on the browser is a ranking factor; however, Google does not the use the PageSpeed tool in this calculation.

3. Do they use the Speed Index?

No, I don’t believe they’re using SpeedIndex. For those who don’t know, SpeedIndex is a WebPagetest metric introduced in 2012 that tries to put emphasis on the visual progress of the page to calculate a number as an indicator of page performance. It’s a great initiative because individual metrics are often misleading. This isn’t a composite metric, per se, but it’s one where the actual visual response of the page is the key to the calculation.

This is something that WebPagetest specifically calculates when it runs a test. And since Google uses the toolbar and onload metrics, and nothing synthetic (I’ll go into the mechanics of how this in question 5), SpeedIndex is not a metric available to them.

4. What about the Google Analytics Site Speed feature?

In 2011, Google added a feature to Google Analytics that measures and reports real-world page speed to Analytics users who turn that feature on. Site Speed lets site owners know which of their pages are fastest and slowest, how page load time varies geographically, and how pages perform for different browsers.

Google Site Speed

You would think that all this data would be useful for factoring page speed into search ranking, but based on their silence on the subject, it would seem that Google doesn’t use any of the data collected in Google Analytics for this purpose. In my opinion, they should, as it would allow them to sample more modern browsers.

5. So how DOES Google gather real-world performance data?

Google uses the Google toolbar to crowdsource data from real users. In my opinion, even though it doesn’t leverage Site Speed, it’s still a solid way to gather meaningful real user data. They’re measuring from users’ actual web browsers and from real bandwidths — no simulations.

Here’s how they do it…

If you’ve installed the Google toolbar on your browser and you’ve activated the “PageRank checking” feature, then you’re helping Google measure load times for the purposes of search ranking. The toolbar measures the actual load time of every page you visit and sends the results back to Google. The results are then aggregated and used to determine real-world speed for each page.

Google toolbar

6. What browsers does the Google toolbar use?

The toolbar functionality is, as you would expect, already embedded in Chrome. The Google toolbar is also available as an add-on for Internet Explorer 6+. It used to be available for Firefox 2-4, but Google discontinued Firefox support in 2011.

7. What exactly does the Google toolbar measure?

It measures onload time: the time it takes for all page resources to render in the browser — from resources you can see, such as text and images, to those you can’t see, such as third-party analytics. (“Onload time” is also known as “document complete time” or “load time”.)

There’s a big caveat here: While onload time is an important measuring stick for performance, it needs to be taken with a grain of salt, because it isn’t an indicator of when a page begins to be interactive. A page with a load time of 10 seconds can be almost fully interactive within 2 to 5 seconds. That’s because onload time can be inflated by third-party content, such as the aforementioned third-party analytics, which users can’t even see.

Key takeaway: If your pages take a long time to get to onload, then according to Google they’re slow — even if they feel fast to your visitors.

8. Which pages does Google measure?

Google measures every page visited by users on your site.

9. What? Even pages I’ve marked as non-crawlable?

That’s right. Because the Google toolbar grabs all user-generated data via each participating user’s browser, it allows Google to measure all the pages your users see, not just what you have told Google is crawlable.

10. In terms of site traffic, at what point does the page speed factor kick in? Are we talking hundreds of thousands of page views per month? Millions?

This is a great question. I wish I had a specific answer. It’s probably a good guess that with more page views, Google cares more, or that there’s a page view critical mass after which speed is fully weighted in rankings.

Something to bear in mind: if you subscribe to the widely held belief that page speed accounts for about 1% of the total algorithm weight, it might explain why sometimes speed doesn’t seem to affect ranking all that much, especially on sites with few page views.

11. What if my page is personalized and has very different content for authenticated users, but the same URL?

The Google toolbar makes no distinction between personalized content if the URL remains the same. All results are averaged together to determine the final score.

12. How will Google factor page speed into mobile search ranking?

Google’s head of search spam, Matt Cutts, announced last month at SMX Advanced that Google is going to roll out a version of its site speed ranking factor for mobile sites. Matt did not specify a time to expect this change to roll out. This dovetails with another Google hint about an upcoming mobile version of PageSpeed Insights, but I don’t feel that the two are related, for the same reasons outlined in the answers to questions 2-4, above.

Based on what we know about how Google gathers real user data via the Google toolbar for desktop, it’s safe to speculate that it could similarly gather mobile user data via its Google Search app. With anywhere between 100 million and 500 million current installs on Android and iOS devices, this is a large enough user group to deliver statistically meaningful results.

13. Will preloading content on a page hurt my ranking?

“Preloading” is an advanced front-end optimization technique that we use in our FastView solution here at Radware. It lets our customers constantly track and analyze how visitors use their site. Then, using this information, it predicts what pages people are most likely to visit next and then pushes page resources to the visitor’s browser so they’re waiting on standby before the visitor even clicks.

Preloading is great because it gives the illusion of nigh-instantaneous page load, but site owners sometimes ask if it’s a trick that Google will reject and possibly even penalize them for. The short answer is no. As I’ve mentioned above, Google’s score is based on the onload time measurement. Preloading doesn’t cheat the system. It simply improves your onload time.

14. Will deferring page resources help my rankings?

“Deferral” is another excellent optimization technique. It allows you to defer non-essential page resources — such as third-party scripts — so that they load after the onload event. Deferral is an honest technique in Google’s books. Anything that helps a page improve its onload time will improve that page’s score.

15. Will a faster “start render time” help my rankings?

“Start render time” is different from “onload time”. As its name suggests, “start render” indicates when content begins to display in the user’s browser. While it can be measured, start render doesn’t indicate whether the first content to populate the browser is useful or simply ads and widgets.

Having said that, start render time is still a useful measurement because, over time, it gives good insight into the performance health of a page. This is neither here nor there, because, as I’ve already mentioned, Google doesn’t factor start render into its results, instead focusing exclusively on onload time.

16. Are there any mobile-specific tactics I can use to help mobile search ranking for my site?

While site speed may not be a mobile ranking factor for a while, other user experience issues will be a factor very soon. Last month Google also announced that they plan to roll out several ranking changes in the near future that address sites that are misconfigured for smartphone users. The announcement mentioned two common mobile configuration mistakes that site owners should be mindful of:

  • Faulty redirects — When a page redirects a user to a generic mobile-optimized page, rather than a mobile-optimized version of the specific page they were searching for.
  • Smartphone-only error — When mobile users are served an error page from search, instead of the page they were looking for.

After addressing these two issues, you can explore Google’s comprehensive list of recommendations for webmasters who want to optimize for mobile.

17. My site is already pretty fast. Is there a cutoff point at which making it faster won’t affect its SEO rank?

Pages that are already fast probably won’t experience a difference. If you’re taking your load time from 10 seconds down to 3 seconds, that’s a significant improvement that will likely help you. If you’re taking load times from 2 seconds to 1 second, you probably won’t see any real results.

You also have to consider how fast your pages are compared to the pages you’re competing against. If improving your load time makes you significantly faster than your competitors, you may notice a difference. If you were already faster than your competitors, not so much.

18. How much should I care about page speed?

Questions 1-17 cover the “How do they do it?” questions. It’s tougher to answer the “How much should I care?” question. I’ve read arguments that making pages faster did little to nothing to improve search ranking, and I’ve read case studies from companies that say they’ve made their pages faster and grown organic traffic anywhere between 20 percent and 40 percent.

It’s important to bear in mind that SEO is just one benefit of serving faster pages. Our customers also report dramatic increases in metrics like revenue, conversions, page views, customer retention, and application adoption. In other words, if you care about the entire end-to-end user experience — from your visitors being able to find your site quickly to being able to navigate and complete whatever tasks they need to complete — then you should care about speed.

Tammy Everts

As a former senior researcher, writer, and solution evangelist for Radware, Tammy Everts spent years researching the technical, business, and human factor sides of web/application performance. Before joining Radware, Tammy shared her research findings through countless blog posts, presentations, case studies, whitepapers, articles, reports, and infographics for Strangeloop Networks.

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