Why Site Speed Matters to CROs

by Art

Last updated on September 7th, 2018

There’s an old adage that a woman decides whether or not she’s interested in a man 30 seconds after meeting him. A study in 2010 actually suggests that this figure is closer to 3 minutes.

Either way, the point remains that first impressions are extremely important.

Those of us over a certain age might remember being patient enough to leave the computer running all night to download an album using LimeWire, but such days are long gone.

In 2014, it was reported that a huge 57% of users will abandon a page if it takes longer than 3 seconds to load.

limewire screenshot

Balancing speed with testing

One potential problem for CRO testers is that adding snippets for analytics services or A/B testing services like Optimizely or VWO can slow your site speed.

It can also be slowed by introducing images that aren’t effectively optimized—because you’re just testing, not building a permanent page yet.

But simply stopping to do all of this stuff isn’t an option for CRO testers, so it becomes necessary to look for solutions elsewhere.

Site speed might not be something you think about that much but, when you know a little more about its impact on conversions, it might end up being your next big focus!

Below you’ll find three of the aims that one of our partners—Squirrel Hosting—had when redesigning their website, as well as how they accomplished it. We’ll also highlight how you can apply that experience to your own site.

Aim #1: Speed up the site

squirrel hosting speed test

Achieved by:

Using sprites for images to lower requests

Building a larger image from multiple smaller images might seem like an odd way to improve page speed, especially as it can result in a higher image file size.

However, using sprites allows for multiple images to be loaded with a single HTTP request.

Optimizing images

There are plenty of plugins out there that will help with this, but if you don’t want to use them, just make sure any images you upload aren’t any bigger than they need to be.

For example, if your site has a max width of 600 pixels, there’s no need to upload images much bigger than that if they’re not going to be clicked on.

Combining files and minifying them where possible (e.g. CSS)

Sounds scarier than it is. Minifying can help you reduce HTTP requests and compress unwieldy code into something more manageable. Reducing requests is something else Squirrel Hosting focused on, taking theirs down from 74 to 29.

Using CSS to create the page layout instead of relying on images

You can see this for yourself when you look at their homepage. Buttons and boxes are created from CSS rather than using images, which can break or fail to show up for some users.

The big takeaway?

You’ll have more success doing lots of little things to speed your site up than trying to find a single golden bullet that will improve everything at once. Keep shaving away 0.2 seconds here and 0.1 seconds there, and it really will add up.

Squirrel’s efforts saw their theoretical maximum page load time drop to around 500ms—half that of their initial 1-second target. But their need for a live chat plugin and SSL badge means that their actual load time is just shy of 3 seconds.

If your site is slow, think about whether you really need those plugins. They may well be holding your site back from meeting its potential.

Learn how to run a speed optimization

Aim #2: Mobile/tablet friendly

Mobile and tablet traffic is taking a bigger slice of web traffic every year, and it’s increasingly important to provide a pleasing mobile experience.

Squirrel took that to heart, attempting to make their site 100% responsive by using a scalable design and media queries, with many “snap points” and non-fixed values.

With Google releasing a significant mobile-friendly ranking algorithm in April 2015, colloquially known as Mobilegeddon, mobile accessibility must be taken very seriously.

google mobile friendly tool

Google has a tool that you can use to check how mobile-friendly your site is. It only takes a few seconds to run, and having peace of mind that your site is truly accessible on mobiles and tablets is pretty valuable.

The big takeaway?

Having large images on your website might look great on a desktop or laptop, but it can seriously slow down performance on mobiles and tablets. Look into using media queries to shrink them or even hide them completely.

With mobile accessibility now a significant ranking factor for SEO, that can help you bring in more traffic for use when you’re running split tests and obtain statistically significant results more quickly.

Aim #3: Improve usability

Walnut with zip isolated on white

What exactly does usability have to do with site speed? Plenty! When developers were able to combine files and streamline Firefox’s homepage to make it 2.2 seconds faster, the number of downloads increased by 15.4%.

In addition, stripping back pages­—especially purchase pages—of fancy widgets and pop-up windows can both keep users focused on the path you want them to take and speed up the process of navigating the page.

For Squirrel, this meant stripping away unnecessary imagery, condensing copy as much as possible and offering clear guidance throughout the checkout process. For example, they only used green buttons for checkout.

The big takeaway?

Usability from a design perspective, site speed and improving conversions might seem like three very different things but there are ways in which they all combine to impact the overall experience of a website.

Final thoughts

Site speed isn’t a particularly sexy metric. It’s one that many A/B testers and marketers think falls under the responsibility of the dev team. However, as we’ve seen above, things aren’t that simple.

Because widgets for things like split testing and analytics can slow your site down, you owe it to yourself—and to the rest of your team—to speed things up as much as possible by streamlining in other ways.

The above points don’t represent the only things you can do to speed up a site, but they’re a good place to start!

Got any tips for website owners looking to speed up their site that we haven’t covered? Let us know in the comments. Thanks to our partners at Squirrel Hosting for baring their soul (and their redesign process) to us for this post.

Read other Crazy Egg articles by Art.

No Comments


Get updates on new articles, webinars and other opportunities:


Art is a freelance copywriter/content marketer based in the UK. He's worked with both startups and large corporations on topics ranging from fitness to tech and business issues.


Comment Policy

Please join the conversation! We like long and thoughtful communication.
Abrupt comments and gibberish will not be approved. Please, only use your real name, not your business name or keywords. We rarely allow links in your comment.
Finally, please use your favorite personal social media profile for the website field.


Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Show Me My Heatmap

Looking for key #Webanalytics tools? Try @CrazyEgg for the best way to track your #digitalmarketing efforts in a simple to read #data form

Brad Chuck


What makes people leave your website?