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From Milliseconds
 to Millions: A Look at the Numbers Powering Web Performance

Harry Roberts
November 08, 2019

From Milliseconds
 to Millions: A Look at the Numbers Powering Web Performance

We all know performance is big business, but how big? Let’s take a look at some of the numbers powering the web performance industry from both sides of the table. What do performance improvements mean for my clients, and how do we translate that into a working relationship?

Harry Roberts

November 08, 2019

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  1. From Milliseconds to Millions A Look at the Numbers Powering

    Web Performance
  2. Hi, I’m Harry Consultant Performance Engineer Leeds, UK @csswizardry

  3. None
  4. From clearfixes to waterfalls.

  5. Ask the Right Questions

  6. I don’t have all of the answers.

  7. Ask the Right Questions How do you know the site

    is slow? What key areas of the site should I look at? What will it being faster mean for the business? How do you intend to measure this?
  8. Nobody Wants a Faster Website

  9. They want the most effective website.

  10. Motives Increase revenues Improve engagement Drive sign-ups Raise conversions Solicit

    donations Deliver content
  11. Case Study

  12. We want to be faster but still run the same

    number of ads. Publishing Client “

  14. How much can we get away with?

  15. None
  16. You Can’t Fix What You Can’t Measure

  17. Gather Data Spend time gathering statistics Then spend some more

  18. None
  19. Google Analytics Average data means means—we want percentiles Only samples

    1% of sessions—insufficient for many sites Far too coarse—aggregates every device, browser, page, region Focuses on load times—considered a legacy metric
  20. Any data is better than none.

  21. Case Study

  22. Do you know about your Venezuela problem? “

  23. Do you know about your Venezuela problem? “

  24. None
  25. Venezuela Economy is tanked Government minted Petro Electricity is virtually

  26. None
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  32. Follow the Numbers

  33. Numbers seldom lie.

  34. Case Study

  35. None
  36. <head> <script>...</script> <meta name="viewport" content="width=device-width, minimum-scale=1.0" /> <link rel="stylesheet" href="/app.css"

    /> <script src="/app.js"></script> <meta charset="UTF-8" /> <title>...</title> </head>
  37. <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, minimum-scale=1.0" /> <title>...</title>

    <script src="/app.js"></script> <script>...</script> <link rel="stylesheet" href="/app.css" /> </head>
  38. It got slower.

  39. Move Slow to Move Fast

  40. There is probably no rush.

  41. Take your time to measure.

  42. Release incrementally.

  43. One thematic release per day.

  44. What Has Most Impact? Know where to look next time

    Know what to avoid next time
  45. Maximise the Work Not Done

  46. It’s just as important to know what not to do.

  47. Case Study

  48. None
  49. Most conversions happen at 2s but our median is 2.9s.

  50. Case Study

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  53. There is no prize beyond first place.

  54. Let’s Ignore Load Already the best on desktop and mobile

    It’s a legacy metric anyway We’re definitely suffering with Start Render Everyone hitting the site wants to see stuff Start Render is our focus
  55. Load is subresources; Start Render is <head>.

  56. A week in their <head>.


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  60. Pricing Performance

  61. Don’t do it for the money, but never do it

    for no money. Oliver Reichenstein “
  62. Performance directly affects the bottom line.

  63. This is not a good time to be shy.

  64. Case Study

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  66. 03.s average [reduction in] latency across our funnel equals £8m

    a year in additional revenue. csswz.it/2FQHt2S “
  67. Value-Based Pricing.

  68. My fee represents my contribution to the project with a

    dramatic ROI for you and equitable compensation for me. Alan Weiss “
  69. How much are we likely to make from this project?

  70. How have you calculated the value of this project?

  71. I am not your Business Analyst.

  72. But I can be for a little bit.

  73. Phase Zero.

  74. Phase Zero A period of pre-engagement Let’s work out the

    value of the project together Then we know how much it’s worth to you… …and I know what to charge you.
  75. None
  76. Customer Data and A/B Tests.

  77. 3× more conversions if we start rendering under 3s compared

    to after 6s
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  79. 62.1% 87.5% Bounce Rate With and Without Cloud.typography

  80. Now we can put numbers against it.

  81. If we can achieve a start render of 0.9s, we

    stand to increase conversions by 8%. Across one year, this equates to increased revenues of £1–1.2m. I’ll take X%. “
  82. Keep on Top of Things

  83. Performance budgets, pragmatically.

  84. How should we set performance budgets?

  85. Set to your worst point in the last two weeks.

  86. 0.8s under budget: new budget set to 2.2s

  87. Only just staying in budget: leave as-is but don’t slip

  88. Yikes! Lots of work to do here: budget is overshot

  89. Normalise performance.

  90. Normalise Performance Talk about it like it’s always been there

    Mention it in passing Have dashboards for individual teams
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  92. Ultimately blur the lines.

  93. Performance is a proxy for business success.

  94. Know When to Stop

  95. Good enough is good enough.

  96. Thank You Very Much

  97. Thank You Understand the situation fully before you begin Maximise

    the work not done Calculate the value of the project Know when to stop
  98. harry.is/for-hire