Updated: 10 Jan 2024
The web performance community often says that "performance matters", but why is that? Does it truly matter? What are the reasons? Whether you're new to this topic or want to better understand the arguments, this article is for you.
Performance is important primarily because it improves user experience. This core reason drives all the other ones. It's why Google added performance data to their search engine rankings. Faster websites mean better business results as well as improved social and environmental outcomes. Let's dig into the details…
1. Performance improves user experience Jump to heading
The core reason why we care about web performance is that it improves user experience when they interact with the web. When Google launched the Core Web Vitals, they based the thresholds partially on scientific research on human-computer interaction. Studies, and perhaps your own experience, show that:
- Humans lose focus as wait time increases beyond 0.3-3 seconds.
- Humans perceive a response to an interaction as instantaneous if it's less than 0.1 seconds. More than 0.3 seconds, and users perceive a poor experience.
Of course, full user journeys on the web are complicated, and context matters. To understand more about the science and reasoning behind it, check out The Science Behind Web Vitals.
Reality and perception are not equal Jump to heading
The story of Houston's baggage claim woes is often shared in the performance world. To summarize, the airport received many complaints about baggage claim taking too long. They improved their process to match the industry benchmark. However, the complaints did not go down!
They went back and observed the user journey with a more open eye to the differences versus other airports and discovered the walking time was much shorter in Houston. So, they contrived a longer walking distance to baggage claim, and the complaints finally went down.
Often the psychology of queuing is more important than the statistics of the wait itself.
–Richard Larson, MIT operations researcher
In essence, "occupied time" is less painful than "unoccupied time". This story illustrates just one way that user perception is not always the same as reality.
2. Performance leads to better business results Jump to heading
When users are happy, they are less likely to abandon your page before finishing the job they came to your website to do. Whether that's purchasing a new item, signing up for a subscription, or whatever constitutes a "conversion" for you.
Yelp reduced First Contentful Paint (75th percentile) by 45% and Yelp Page Complete (75th percentile) by 25% and saw a 15% improvement in their conversion rate.
–Reported on WPOstats.com
Countless case studies have been published linking web performance and key business metrics like bounce rate and conversions. You can see many soundbite examples at WPOstats.com.
We're working on publishing Shopify-specific case studies, the first of which is now live! Read more about how Sunday Citizen reduced bounce rate and increased conversions by improving their web performance.
How performance impacts SEO Jump to heading
Search engines try to offer the best content results for a user. Google considers how a user experiences a website to contribute to the quality of that content. Thus, in 2021, they added web performance data to their search engine ranking algorithm. Specifically, they measure the Core Web Vitals.
We don't know exactly how performance impacts search ranking, but content is still king. If your content quality is above competitor websites, you might be impacted less. However, for two sites with close to equivalent content quality, the faster one is more likely to be ranked higher. The lesson here is don't let web performance be the reason why you're ranked lower.
3. Performance increases equity and access Jump to heading
When we construct the digital world to the limits of the best devices, we build a less usable one for 80+% of the world's users.
–Alex Russell, Microsoft Edge partner product manager
A great divide exists between the fastest mobile devices and all the rest of them. While high-end phones keep pushing the limit on processing speeds, mid- and low-range phones have barely improved or even stagnated. This means that the bulk of the market is not seeing the same improvements that those at the highest ends who can afford $800 phones are seeing.
In addition, not everyone has access to fast, reliable connection speeds. Move away from densely populated areas, and this problem is quite common.
If you want to dive deep into the data behind this, check out The Mobile Performance Inequality Gap, 2021 by Alex Russell.
Your analytics are wrong Jump to heading
You may not be aware, but a lot of things have to happen before analytics data gets sent. This means that your data contains "survivorship bias":
The users who have the worst experiences are likely to be phantom bounces: they don't appear in your analytics or intelligence tools because they don't hang around long enough for the app to load and analytics to fire.
–Simon Hearne, web performance expert
In his article, Simon shares some excellent data from Chrome that shows abandonment rates increase as First Contentful Paint (FCP) takes longer. None of these experiences are tracked in your analytics so your data is biased.
Optimizing for the longer tail of poor performance can help bring these users into your site. One unexpected consequence is that your metrics may move down as you've increased the traffic from lower-end devices and networks. In these cases, it's not a bad thing though–performance for each user is actually faster, and you've increased the ability for more people to access your website thereby increasing total conversions.
4. Performance can make the web greener Jump to heading
The environmental cost of the web and our dependence on mobile devices is larger than you may think. Sustainability is more complex than only power usage, but statistics can be difficult to find. However, if we look at power consumption alone, Information and Communication Technology (ICT) was estimated to comprise up to 7% of global electricity in 2020 (source).
By reducing the amount of power a device needs for a user to load and use your website, you can contribute to a greener web and longer battery life. For example, processing JavaScript is more expensive than any other asset type. Additionally, video consumes more power than images. Finally, optimizing for user experience so that a user can complete a task faster resulting in less total screen time can greatly reduce the power consumption of a single session, especially when performed on large monitors or on slower networks.
Conclusion Jump to heading
To review, web performance is important because a faster website with fewer frustrations improves user experience. Improved user experience results in lower bounce rates and higher conversions, ultimately helping your bottom-line business results.
Even outside of economic reasons, performance is important. It increases the accessibility of your site for more people both globally and locally. Additionally, we can reduce the carbon cost of our sites when we optimize for performance.
Whether you're a bottom-line focused capitalist or more concerned about equity and the environment, working toward better performance is the right move.