Conversion Rate Optimization

Conversion Rate Optimization is crucial for optimizing websites and digital products

In today’s digital age, businesses are constantly updating their websites and products to improve performance and drive growth. These can be minor tweaks to completely new features, algorithms, or redesigns.

Data shows only 25% of these changes positively impact your most important goals. The other 75% either makes no difference or even has a negative impact on your goals. This means that all these changes barely result in growth. That is where Conversion Rate Optimization comes in.

What is Conversion Rate Optimization?


Conversion Rate Optimization (CRO) is a way of working. It is a systematic approach to increasing your website’s conversion rates, improving your products, validating your hypotheses and ideas, and gathering knowledge about your customers.

It involves conducting research and using experiments to identify the changes that will have the biggest impact on conversions. This means that instead of implementing changes that barely result in growth, businesses can focus on the changes that will drive rapid growth and alignment with customers.

CRO generally starts in the e-commerce or marketing department, and is executed by a single CRO specialist or a small team.


Why Conversion Rate Optimization?


Instead of implementing every change on the website or product, teams can now implement only changes that result in an improved user experience and higher conversions.


Companies can learn a lot about what drives their customers and revenue by conducting user, data, and scientific research and running experiments. This knowledge is beneficial for the whole company.


The combination of growth and knowledge results in a company that is future-proof. Evidence-based growth through data, innovation, and experimentation ensure the company stays competitive in the future.

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How the tech giants use Conversion Rate Optimization

The tech giants have adopted this way of working long ago with great results. In fact, Conversion Rate Optimization is embedded in the entire organization. Everyone can set up and run experiments and make decisions based on the outcome without interference from management.

CRO has become experimentation for these companies, and they have an experimentation culture.

In the image you see the growth of these companies compared to the growth of the S&P500 companies. These tech companies have adopted this way of working throughout the whole organization. Netflix, Microsoft, and Booking openly share this in their tech blogs.

For other companies to survive and thrive in this digital age, they must adopt the same principles.

Stock prices experimentation tech giants

The Conversion Rate Optimization process

Conversion Rate Optimization process

In the image above, you see the Conversion Rate Optimization process. It starts in the bottom left with your optimization research. This contains your data, user, and scientific research.

Your research will give you many insights, which you will combine in the next stage to craft test ideas. Next, you need to prioritize them. There are many prioritization models, with evidence-based prioritization being the best once you complete 40+ tests. Next, you must create hypotheses for the ideas with the highest priority score.

When an idea gets to the test phase, a designer and developer should create the test. After the test has run, you analyze the results and draw learnings.

If you want to learn every step of the Conversion Rate Optimization process, check out my Udemy course, ‘The complete Conversion Rate Optimization course.’ You can find a link on the courses page with a huge discount.

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The Hierarchy of evidence

Hierarchy of evidence for Conversion Rate Optimization

When working on CRO, it is important to know the hierarchy of evidence. This model comes from science and was introduced to CRO by Ton Wesseling, founder of Online Dialogue.

The pyramid ranks the strength of results obtained from research. Higher up in the pyramid means a higher quality of proof.

At the bottom of the pyramid, we have the expert opinion, best practices, and competitor analysis. Next, we have user research. Then, on top of that, there’s data and science. And at the top of the pyramid are A/B testing and meta-analysis.

A meta-analysis combines the results of multiple A/B tests. A meta-analysis can be conducted when multiple A/B tests address one overarching hypothesis.

In short: use user, data, and scientific research to develop A/B tests. After you have conducted multiple A/B tests, combine the results and analyze what you learned.

Optimization Research

Research is of great importance to be successful at CRO. Good and proper research and findings from that research will result in valuable insights into your digital users’ needs, motivations, and behaviors. It will also result in better hypotheses and, therefore, much more successful A/B tests.

There are many forms of research. The best input for your A/B tests comes from user research, data, and science. Of course, expert opinion and best practices are useful if you don’t have any data or user insights yet.

When you start with your research, your quantitative data is the best place to start, like data in Google Analytics. Your data will tell you exactly what happens on your website and give a great indication of where you should improve. After quantitative data, do user research and check scientific articles to find possible reasons why your users behave the way they do.

From all research insights, create strong hypotheses and test possible solutions to optimize your website and digital products.

Optimization research

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Psychology and CRO

Online psychology and persuasion for Conversion Optimization course

By combining CRO with psychology, you will not only know what happens on your website, but also why it happens. You will understand all the insights you get from your data, your user research, and of course, from your A/B test results. You will know why visitors convert, why they don’t and why they behave the way they do.

Start by selecting a psychological framework and document the applied strategy to your A/B tests.

There are several frameworks. Choose the one you prefer:

  • In my online psychology course I define four strategies: Cognitive ease, attention & perception, motivation & risk, choices & memory.
  • Online Dialogue’s BOOM model defines five strategies: Ability, motivation, attention, certainty, and choice architecture
  • BJ Fogg’s model has motivation, ability and prompt
  • The Lever model of has cost, trust, usability, comprehension, and motivation

Use a framework to learn what works best in your customer journey. You can get my Online Psychology and Persuasion course with a discount on the online course page.

The Conversion Rate Optimization Team

In the early stages of Conversion Optimization in an organization, a single CRO specialist does all the work. This specialist does the research, sets the hypothesis, writes the code for your test, makes the designs, knows about psychology, does the copy testing, and everything else.

Once a company starts believing in CRO and invests more, it becomes a team effort. A developer and UX designer will generally be the first to join. Next, an analyst, UX researcher, psychologist, and copywriter could be added.

The next step would be to have several teams working on Conversion Rate Optimization.

When CRO becomes even bigger, the original team gets more responsibilities and starts teaching others, like the product teams, to run experiments. So, more people run more tests more efficiently with better results.

Eventually, everyone in the company can set up and run experiments supported by a Center of Excellence. The Center of Excellence, generally, consists of several specialists and is responsible for the optimization within the whole organization.

CRO Center of Excellence

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Conversion Rate Optimization tools

There are several tools needed for CRO: research tools, testing tools, statistical tools, and a tool for documentation.

Thanks to the growing popularity of my CRO courses and CRO Tips newsletter, I’ve secured exclusive deals with several great tool vendors.


Research tools

In the research phase, data tools, heatmap and recording tools, and user research tools help you develop ideas to test on your website. Also, tools to evaluate your site speed can be useful here. Google Analytics, Mouseflow and Hotjar are great tools.

Statistical tools

You need statistical tools before you run a test and when you analyze it. ABTestguide and Speero’s calculator are great free tools for your statistical calculations. Alternatively, you can use Blast Analytics for non-binomial metrics (like revenue).

Testing tools

To run experiments you need a testing tool. There are many tools for this, ranging from entirely free to thousands of dollars per month. Alternatively, you could also build your own tool. Convert, Optimizely, VWO, AB Tasty, and Kameleoon are widely used.

Documentation tools

An essential tool is one that helps you keep a clear overview of your CRO process and document your insights. You want to see who is doing what, your team’s progress, and where you are successful. Airtable is an excellent tool for this.

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Step-by-step CRO

I enjoyed explaining CRO for those new to the industry in a vlog for the YouTube channel ‘Tips with Punch.’ After checking it out, my mom told me: “Now I finally understand what you do.” 🙂

Conversion Rate Optimization courses

I believe that if you find your passion in your work, you should also use it to help and inspire others. That is why I created several high-quality, complete, affordable Conversion Rate Optimization courses so others can learn and excel in this work. These are video courses that you can follow at your own pace. You can find them with great discounts on my online courses page. I am also one of the teachers in the CXL course ‘Advanced Experimentation Masterclass.’

If you lack the budget, feel free to email me at, and I will give you free access to the courses you need.

The Complete Conversion Rate Optimization course

This course helps you master every step of the CRO process, get more A/B test winners, and become a Conversion Rate Optimization expert.

Change Management from CRO to an Experimentation Culture

Change Management: from CRO to Experimentation Maturity

Assess the maturity level, write and pitch a plan, apply Change Management and grow toward an Experimentation Culture

Coding for AB testing

Coding for A/B testing: Run more A/B tests, find more winners

Learn HTML, CSS, JS & data tracking for A/B testing and build your own A/B tests without the help of a developer.

Online psychology and persuasion for Conversion Optimization

Online Psychology and Persuasion for Conversion Optimization

Apply online psychology in a structured way in your conversion rate optimization program to get better results.

Conversion Rate Optimization process insights in Airtable

Conversion Rate Optimization process & insights in Airtable

Get the best overview of your Conversion Rate Optimization process, see your progress and gather insights in Airtable.

Advanced Experimentation Masterclass

An extensive 4,5 hours course drawing from our experience in experimentation and teaching. This course covers a wide array of advanced topics.

Receive free CRO tips, the Online Psychology for A/B testing book & more