GRO Talks 266

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Presorted first class mail. It’s the CRO Roundtable Roundup!

Thanks to Matt BeischelIqbal Ali, Veronika Morozová, Craig Sullivan, and David Swinstead for joining us. Want to get in on the action and talk with other cool GRO people? Then you should probably…

One Sentence Takeaway

I’m a busy person; give me the TL:DR

Ensuring proper script placement and performance testing is critical to reliable experimentation and improved user experience.

The Notes

What we discussed this week

  • A/B Test Tool Performance Impacts
    • The problems with using “body blocker” anti-flash CSS injection
    • Loading experimentation scripts in head avoids UI flicker
    • Performance trade-offs when scripts run early versus deferred
    • Measuring impact on first contentful paint
    • Render-blocking versus async loading strategies
    • Perform web speed testing to confirm the actual impact of test tool scripts
    • Vendor responsibility for optimized implementation
  • Experimentation Implementation Practices
    • Equal performance delay across variants prevents skew
    • Archive unused scripts to reduce performance drag
    • Avoid hacky anti-flash methods for better stability
    • Dealing with reluctance to risk slower page performance
  • Conferences and Community Events
    • Recent hot topics include AI, growth, and scale experimentation
    • Smaller events provide stronger networking opportunities
    • Conversion Hotel is a top CRO conference
    • Measure Fest and Brighton SEO are also good alternatives
    • Pros and cons of long sessions versus short talks
  • Professional Travel to Conferences
    • Company budgets often restrict conference attendance
    • Comparing travel options for convenience and cost
    • Getting event organizers to cover costs for speakers
    • Maximizing budgets with free tickets

Hey all you cool GRO People!

GRO Talks Live returns to the winter 2025 Experimentation Elite conference with a heaping helping of in-person roundtable sessions, and we want to see you there!

GRO Talks Live Roundtables
December 9th, 2025
155 Bishopsgate, London, EC2M 3YD

The Quotes

Standout quips from this week

"As long as both variants are seeing the same performance delay, it doesn't really matter, does it?"
"I had to spend like a whole day poking and prodding to finally figure out that the test tool was causing the problem."
"You just need to make sure that you're not doing anything super hacky and cowboyish."
"To say that they are not adding value might be an understatement."
"Sometimes smaller conferences are better because then you have more chance to talk with the people, and even with the speakers."

Book Club

Relevant reads recommended this week

No books this week, sorry!

Off-Topic Sidebars

Experimentation isn’t the only thing we talk about at the CRO Roundtable. There’s often a healthy dose of discussion on shared interests, personal passions, and hobbies.

  • International Talk Like a Pirate Day
  • Being a DJ
    • learning new music mixing styles

Sidebar Shareables

Amusing sidebar content shared this week

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