About us

What is CRO-tool?

CRO-tool is a database containing cognitive biases, mental models, tactics, etc. that apply to conversion optimization and user research. We’ve made it easy for you to see which bias is relevant at which moment and how these biases can be applied for experiments.

Using CRO-tool you can easily narrow down the biases you want to know more about, explore new findings, and add this extra layer of psychology to your CRO process.

How does it fit into the CRO process?

The basic conversion optimization process contains 3 phases.

Phase 1: Optimization research

During this phase, research has the focus. User research, data research, science, expert opinions, best practices, etc. You’ll get insights into your users and know what obstacles they run into.

Phase 2: Creating the backlog

Combine all the insights you’ve gathered during phase 1. Write multiple hypotheses based on the findings, and prioritize what hypothesis is the most important to experiment with first.

Phase 3: Experimentation

Wireframe, design, pre-test analysis, build the experiment, experiment analysis, collect learnings, reporting, IT backlog. All terms you’re probably familiar with.

CRO-tool can be added in phase 2. While writing your hypothesis, based on (multiple) insights from different sources, you know where the problem is. You’ve now got to think about potential solutions. The question here is: Why would the solution work? What is your solution based on?

This is where CRO-tool comes in. CRO is data-driven, just like science. What if you would combine your solution with psychology? In that case, you would exactly know why your experiment worked, or not.

These findings are essential for your next experiments. You’ll get to know your audience because of the psychology you’ve included in the process.

Why are my users behaving like this? How can we change their behavior? What works and what doesn’t? Can we apply this bias further down the funnel?

The findings can also help to improve processes


Marion Ravel

Marion Ravel

Marion Ravel is the newest member of CRO-tool and is responsible for all the content, user research (interviews), and marketing. She remotely works from the beautiful city of Marseille in France and is always up for having a chat about the product. She’s the one to reach out to if you want to have anything changed in the product.

Marion Ravel

Roelof Jan Elsinga

Roelof Jan Elsinga set up the whole digital ecosystem of CRO-tool. He’s maintaining the database, backend development, and server. If we kindly ask, he’s also up for doing some front-end development. Roelof Jan is always the one to say no to our ideas, which is good! That way we maintain focus.

Marion Ravel

Sander Volbeda

Sander is the founder of CRO-tool who came up with the idea to build this specific product. He’s responsible for the overall view of the product. Doing some content, design, front-end, and much more. If you would like to talk to somebody about the entire CRO process, he’s your guy.


CRO-tool was founded in 2019 after Sander noticed how hard it was for him to dive into all these relevant cognitive biases for conversion optimization. With a bachelor's degree in Communication and Multimedia Design, it was hard for him to get started with psychology. For sure, some books can be read, but this takes time.

Sander came up with the idea to create a small search engine for cognitive biases that are relevant for conversion optimization. This would solve the problem of making cognitive biases accessible.

It soon turned out to be a ‘big’ challenge to write all the content, gather examples with them, and build the website. Soon, Roelof Jan joined him for all the technical development tasks. Sander and Roelof Jan started to build the product.

The hard part wasn’t to create the search engine, but to find out how our users search/filter their data. You can already imagine that there were a lot of tasks to be done. Solving the problems our users have was and still is the main task while improving the product.

In early 2022 Marion joined CRO-tool as a co-founder. We’ve officially become an international team! Marion is responsible for updating and adding new content. She’s also the one that focuses on talking to our users (is that you?).

We’re continuing to improve the product every day. We would like to become a CRO documentation tool where psychology is important, so we’re working towards that goal!

- Sander Volbeda. Founder of CRO-tool

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