Connecting the Dots Between Site Speed, User Experience & Your Business [WebExpo 2025]

What do the most successful websites have in common? They’re all fast. Faster sites have happier users. Those happy users visit your site more often and spend more money. But how do you know how fast you need to be? Industry stats and case studies tell only part of the story. You need to analyse your own user data to know when your site is fast enough to benefit your business – and when page slowdowns are hurting it.

In this talk, I share insights from my research into the business value of site speed. I also demonstrate how (and why) to gather real user data, know how fast YOU need to be, create a better user experience, and improve the business metrics that matter to you – from bounce rate to conversions.

Transcript

1. Connecting the dots between… site speed user experience your business @tammyeverts #WebExpo 2025
3. 3 @tammyeverts.com /tammyeverts
5. speedcurve.com/benchmarks
6. Web Performance Guide speedcurve.com/web-performance-guide/
9. Why should I care?
10. Why should I care? How do I measure site speed?
11. Why should I care? How do I measure site speed? How fast should my site be?
12. Why should I care? How do I measure site speed? How fast should my site be? How do I make it faster?
13. “web stress”
14. “web stress” When apps or sites are slow, we concentrate up to 50% harder to stay on task
16. People feel slowness in the moment
17. Frustration increases between 11.5% and 26% during browsing and checkout
18. People feel slowness after they leave your site
19. fast slow
20. content “boring”
21. content visual design “boring” “tacky” “confusing”
22. content visual design usability “boring” “tacky” “confusing” “frustrating” ‘hard to navigate”
23. People feel slowness long after they leave your site
25. If you do not consider time as a usability factor, you are missing a fundamental aspect of the user experience.
26. How can I measure page speed?
27. Performance monitoring tools Synthetic monitoring (lab) Mimics defined network & browser conditions No installation required Limited URLs Limited test locations Compare any sites Detailed analysis & visuals Real user monitoring (field) Real network & browser conditions Requires JavaScript installation Large sample size (up to 100%) Geographic spread Only measure your own site Correlation with other metrics (e.g., bounce rate)
28. Real user monitoring Helps you understand your users and how they experience your site
29. Synthetic monitoring Helps you understand your pages and what you need to fix to improve UX
31. What metrics should I focus on?
33. Is the page loading?
34. Is the page loading? Can I use it?
35. Is the page loading? Can I use it? How does it feel?
36. Is the page loading? Can I use it? How does it feel? Does it correlate with business metrics?
37. Meaningful content Usable out of the box Broad browser support Synthetic RUM Correlates to business/UX Time to First Byte ★ ★ ★ ★ ☆ Start Render ☆ ★ ★ ★ ★ ★ Largest Contentful Paint ☆ ★ ★ ★ ★ Cumulative Layout Shift ☆ ★ ★ ★ Interaction to Next Paint ★ ★ ★ speedcurve.com/web-performance-guide/glossary-of-web-performance-metrics/
38. How fast should my site be?
39. Real user monitoring Helps you understand your users and how they experience your site
40. Identify the conversion peak
41. speedcurve.com/blog/site-speed-business-correlation/
42. 1.1 second Largest Contentful Paint (LCP) 6.2% conversion rate speedcurve.com/blog/site-speed-business-correlation/
43. Locate the performance plateau
44. speedcurve.com/blog/web-performance-plateau/
45. Understand your goal vs threshold
46. speedcurve.com/blog/site-speed-business-correlation/ 1.1 second is your GOAL 2.8 seconds is your THRESHOLD
47. What do I need to fix?
50. Not all pages are equal
51. 1. Product 2. Category 3. Home 4. Cart 5. Search Conversion impact // retail sites
52. 1. Article 2. Search 3. Department 4. Home 5. About Engagement impact // media sites
53. Identify the critical rendering path
54. Synthetic monitoring Helps you understand your pages and what you need to fix to improve UX
56. Largest Contentful Paint (LCP) When the main visual element has rendered in the viewport
57. Largest Contentful Paint (LCP) When the main visual element has rendered in the viewport After LCP From a user’s perspective, none of this matters (It does actually matter, but not for our purposes today)
58. Largest Contentful Paint (LCP) When the main visual element has rendered in the viewport After LCP From a user’s perspective, none of this matters (It does actually matter, but not for our purposes today) critical rendering path
59. critical rendering path
60. “The dull boring stuff” ~Andy Davies
61. “The dull boring stuff” ~Andy Davies Scripts (including third parties) speedcurve.com/web-performance-guide/best-practices-for-optimizing-javascript/
62. “The dull boring stuff” ~Andy Davies Scripts (including third parties) Images speedcurve.com/web-performance-guide/best-practices-for-optimizing-images/
63. “The dull boring stuff” ~Andy Davies Scripts (including third parties) Images Defer assets where possible speedcurve.com/web-performance-guide/using-critical-css-for-faster-rendering/
64. Web Performance Guide speedcurve.com/web-performance-guide/
65. Even small changes can have a huge impact
69. Shaved 15KB off logo Ran A/B test Increased bookings chasingwaterfalls.io/episodes/episode-one-with-malek-hakim/
71. 1. Compressed images 2. Deferred image sprite that was blocking rendering 3. Optimized CSS and JS on the critical rendering path
72. 2s improvement in median load time almost 2X mobile conversions
73. 1. Measure! 2. Start with just a few metrics 3. Identify your speed goals (and thresholds) 4. Focus on the pages that matter most 5. Optimize the critical rendering path 6. Keep measuring 7. Celebrate your wins!
75. Děkuju! (Thank you!) :) @tammyeverts.com /tammyeverts