Part 1: Simon Hearne – The What, why and how of Web Performance Testing

07 May 2021
Part 1: Simon Hearne – The What, why and how of Web Performance Testing

In this interview, Bruce Zaayman, Performance Testing Director at Inspired Testing chats with Simon Hearne, Web Performance Architect, speaker and Blogger about Web Performance Testing.

Simon explains why great web experiences will ensure customers will be more likely to convert when engaging with your website.

Simon also helps run the London Web Performance Group (a professional networking and learning group for people whose work depends on delivering content and applications over the web as fast as possible) as well as running the grey QR Code Generator.

“Giving customers a great and fast experience, means they will consume more content, have a more positive impression of your brand and ultimately be more likely to convert which will generate a more positive business outcome.”

- Simon Hearne, Web Performance Architect, speaker and Blogger.

Watch it here:


Interview Highlights
  • How would you describe the difference between traditional load and performance testing and web performance testing?
  • How do you prove the value of performance?
  • What are the upcoming changes in SEO and why is performance important?
  • What makes it exciting to work in web performance?
  • If a client could only do one thing to improve performance, what would it be?
Relevant Links:
Full video script

Hi Everyone, I am Bruce Zaayman, a Performance Testing Director at Inspired Testing. Today I’m joined by Simon Hearne, who is a web performance architect and an expert in web performance testing.He’ll be sharing some of his knowledge and insight around a very interesting and valuable topic.

Welcome Simon, I’m very excited to have this chat with you, let’s jump straight into it…

Give us a little bit of an overview on yourself.

Yes, so I’m a web performance architect which means I don’t write code but I help companies understand how the code that they’re shipping, the websites and apps that they deliver, relate to the user experience their customers have. So a lot of the time I spend helping customers understand the performance that they’re currently delivering, and then working out how users respond to that, how performance relates to business outcomes such as, simple things like bounce rate all the way through to conversion rate and business success, and then help customers work out what are the best things to do to improve both the performance of the websites they’re delivering and the business outcomes to help build success.

So how would you describe the difference between traditional load and performance testing and web performance testing?

It’s a good question and one that’s almost hard to describe. So, with traditional load and performance testing and as well as other functional and non-functional testing, you’re kind of looking for success, and as you’re working towards success which may be a benchmark of a certain number of users per hour, you’re finding bottlenecks and clearing them until you reach the goal.

With web performance it’s much more an art than a science. It’s about working out what is right for your website and your visitors, which could be totally different from a different website, and different set of visitors. To compound that you’ve got all the variables of web performance such as the devices that your customers use, the connections that they have, whether they’ve been to your site before and have assets cached or not, and then on top of that we have a huge number of ways to measure performance, from different metrics different tools, which makes it really hard to say that “this is success”. Unlike with security testing or performance testing, there’s no real boundary for success, it’s just continual improvement and measuring the changes that you make against your business outcomes and goals.

So, yes, it’s more art than science, I think is the easiest way to describe it.

So is that what makes it exciting to work in web performance?

Yeah, exactly that, especially as every client you work with is different, with a different code base, a different set of customers, different business goals, so you never have one day the same as another, which makes it really interesting.

If a client could only do one thing to improve performance, what would it be?

This may seem counter-intuitive but the best results I’ve seen are when customers understand the performance they’re delivering, so get the right set of measurements in place. Everything else kind of falls of the back of that. Any changes you make… there’s no real point in making lots of changes unless you understand what you’re measuring and what you’re trying to achieve. So getting measurement in place is step one.

How do you prove the value of performance?

This is one where I think our industry has struggled in the past, because it’s not like you can make a change and immediately see results. We’ve seen in the past that customers who had bad experiences may not return to a site for up to 3 months. So if you make a change you may still get the benefits of it 3 months later down the line. So the best way we can prove the value of performance at the moment, is to take a snapshot in time of what we were delivering in terms of performance, and what the business outcomes were, then make the changes that we think are going to have an improvement on the user experience that we are delivering and measure again the business metrics and the success of those changes.

It’s nice to do this in a kind of step wise fashion, so release a feature for a month, measure the impact, then release another feature. Hopefully then we can start to see performance trends over time, and see value coming out of the performance work.

What’s nice about performance work is often times it’s not a big investment of engineering time. It can be a really simple tweak like changing a script tag to add a defer attribute.

So often times the investment is very small compared to the the outcome that we get in terms of the return with user experience.

What are the upcoming changes in SEO and why is performance important?

This is really interesting and something that a lot of our clients have started to ask us about, which is the page experience update. This is an update rolling out in May of this year, 2021, where Google will start to take 3 new performance metrics as ranking signals for mobile search.

So these new performance metrics is something that the industry has been needing for a while. They measure not just how fast you deliver HTML to a browser, but how long it takes until the biggest thing on the page is painted, how interactive a page feels when you tap on an element or click a button, and how much the page shifts around as you’re trying to use it. Something I’m sure we’ve all been frustrated by in the past.

So these 3 new metrics will feed into the page experience, ranking signal for mobile search, and if you achieve people’s goals across all 3 of them, you will get a ranking benefit, which is really nice… If you think about a carrot on a stick, this is a carrot, it’s a reason to work on improving performance, because there will be an SEO benefit in coming months.

Simon, in terms of industry focus, is there a specific industry that should really focus on web performance more than the others or is it like retail, is it banking is it insurance or is it any and all of the above?

That’s good question.

I think historically we’ve seen e-commerce and retail make the best out of performance. I think it’s because it’s easier to measure the impact that performance has on business outcomes but that said, we’ve worked with financial institutions on customer acquisition as well as customer retention.

People get frustrated when they have slow experiences and that could be the straw that breaks the camel’s back in terms of customer retention. So, obviously with that acquisition for any company we’ve got all the SEO benefits, or that the bounce rate analysis or high load times result in high bounce rates everyone who has a website will benefit from better performance in general.

But yeah the case studies that are out there in the public domain generally focus on retail because it’s easier to measure the impact. That said, everyone will benefit so there’s no reason not to consider web performance if you’re not in retail.

Simon, we spoke about the fickleness of some of the customers out there. Can you give us some idea of the time it takes someone to decide to move on to another site or an application? Everything gets compared to Tik-Tok or Instagram that’s instant, so can you expand on that a little bit?

Yeah especially if you are looking at the younger generations who spend the majority of their online time with a mobile device. A website is being compared to native apps and native apps in general feel lightning fast because they can be optimized specifically for the device they’re on iOS or Android, whereas the web is a bit more Wild West. You have to send down all your HTML all your application JavaScript and that causes a lot of variability which customers don’t like. So in terms of comparison we’ve seen this golden rule number of 3 seconds. It’s been in the web performance industry for the last 15 years, if you don’t deliver content within 3 seconds you’re likely to lose half of your audience.

Google did a study on this using double-click a good few years ago, but that number hasn’t changed, because the human creature hasn’t evolved that much in the last 15 years.

3 seconds is a good goal to have for delivering all of your content to a customer before they get a little bit irritated and leave.

But the reason they leave is interesting. It’s not because they don’t want to go ahead and commit to a purchase or consume an article, or whatever it is that you’re delivering online, it’s because slow experiences cause stress.

This has been measured a number of times, recently with echoencephalograms in people’s brains, measuring alpha waves as they use slow websites and slow websites can cause increases in stress by up to 50 percent as measured by alpha waves and recently, just last year, Cyberduck did a study using blood pressure, to show you that slow websites are the leading cause of increases in blood pressure while someone is using a website.

That’s even compared to forms not submitting correctly, to annoying popups to auto-playing music, it’s site speed that causes the most stress.

We know stress is a bad thing to have induced in our visitors, so anything we can do to reduce that stress will probably mean a better user experience, better business outcomes and give us a better result from the website and apps that we’re delivering.

And healthier clients.

Bruce Zaayman

Sales Director

Bruce is an Expert in Performance, Automated, and Functional Software Testing solutions and has been with Inspired Testing since its inception in 2016. He is based in London, UK, but used to serve as the Practice Head: Quality Assurance for DVT in Gauteng.

Bruce was part of the pioneering team that spearheaded DVT’s international expansion into the UK, shortly after which Inspired Testing was launched. His expertise allows him to provide clients with excellent testing solutions that integrate frictionlessly into their existing business processes.

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