Testing Mind Map Series: How to Think Like a CRO Pro (Part 35)

Lucia van den Brink
By
April 5, 2023 ·

Interview with Lucia van den Brink

Lucia van den Brink started coding and designing websites at the tender age of 11 and has been fascinated with improving digital experiences ever since. Fast forward to today, and Lucia has become a true experimentation guru, working with startups and billion-dollar companies alike.

Lucia sums up optimization as “shaping the digital world and user’s behavior to fit your goals.” But don’t be fooled by the simplicity of that statement. Lucia emphasizes the importance of bandwidth and MDE calculations, ditching the notion that one brilliant idea will solve everything, and learning to make do with a less-than-perfect setup, tools, and organization.

If there’s one thing that really grinds Lucia’s gears it’s that experimentation is a sure way to get uplifts. (Hint: it’s not.) Lucia’s here to set the record straight and help you get your optimization program to a healthier place.

Let’s dive in…

Lucia, tell us about yourself. What inspired you to get into testing & optimization?

I built my first webshop when I was 11 years old – and I loved it. I had many websites. I kept on improving them, the colors, the code, the content, and the designs. At that time, that was not so easy at all. No WordPress, WooCommerce or Shopify. But since then I’ve always loved the digital world and fascinated by how people move through that space.

For how many years have you been optimizing?

Counting since I was 11 years old, I’d say 20 years. But professionally (a.k.a. making a living with it) about ten years now, of which 7 years for big $100M – $1B brands.

What’s the one resource you recommend to aspiring testers & optimizers?

This is such a hard question. It really depends on where they are in their process. I can only tell that I’ve learned a lot from Ton Wesseling (check his course on CXL) and Ruben de Boer (check his course on Udemy).

Answer in 5 words or less: What is the discipline of optimization to you?

Shaping the digital world and user’s behavior to fit your goals.

What are the top 3 things people MUST understand before they start optimizing?


  • Bandwidth calculations and MDE estimations (and what that means)
  • Letting go of the fallacy that you should have ONE great idea. If you have a hundred ideas, you can be almost certain your great idea is right there.
  • Your setup, tools, and organization will never be perfect. Deal with it the best way you can, improve what can be improved, but don’t only focus on having something better.

How do you treat qualitative & quantitative data to remove bias?

I think focusing on falsification is an important thing in science. So not testing or searching for something to win, but to learn and fail.

What is the most annoying optimization myth you wish would go away?

Experimentation is booming, and agencies are just selling it without knowing on how to do it right. They guarantee uplifts just by putting A / B tests live, and often they don’t know how to deal with data or doing experiments based on research.

The hopeful companies they serve get the wrong impression from Experimentation. It’s not a magic trick. Often they slowly figure out that the data is not trustworthy or not explained correctly, and they either lose their appetite for experimentation or end up with me fixing their experimentation programs, re-educating and re-establishing hope in experimentation (@ www.increase-conversion-rate.com).

CRO Expert Profile Lucia van den Brink

Download the infographic above and add it to your swipe file for a little inspiration when you’re feeling stuck!

Thanks for tuning in to this exclusive interview with Lucia! We hope you’ve gained some valuable insights from their experiences and advice, and we strongly encourage you to put them into action in your own optimization efforts.

Check back twice a month for upcoming interviews! And if you haven’t already, check out our past interviews with CRO legends Gursimran Gujral, Haley Carpenter, Rishi Rawat, Sina Fak, Eden Bidani, Jakub Linowski, Shiva Manjunath, Deborah O’Malley, Andra Baragan, Rich Page, Ruben de Boer, Abi Hough, Alex Birkett, John Ostrowski, Ryan Levander, Ryan Thomas, Bhavik Patel, Siobhan Solberg, Tim Mehta, Rommil Santiago, Steph Le Prevost, Nils Koppelmann, Danielle Schwolow, Kevin Szpak, Marianne Stjernvall, Christoph Böcker, Max Bradley, Samuel Hess, Riccardo Vandra, Lukas Petrauskas, Gabriela Florea, Sean Clanchy, Ryan Webb, and our latest with Tracy Laranjo.

Mobile reading? Scan this QR code and take this blog with you, wherever you go.
Originally published April 05, 2023 - Updated April 01, 2024
Written By
Lucia van den Brink
Edited By
Carmen Apostu
Carmen Apostu
Carmen Apostu
Head of Content at Convert

Start Your 15-Day Free Trial Right Now.
No Credit Card Required

You can always change your preferences later.
You're Almost Done.
Convert is committed to protecting your privacy.

Important. Please Read.

  • Check your inbox for the password to Convert’s trial account.
  • Log in using the link provided in that email.

This sign up flow is built for maximum security. You’re worth it!