How can you use experimental design to identify the root cause of a problem?

1 What is experimental design?

Experimental design is the process of designing and executing experiments that allow you to test the effects of different factors and variables on a desired outcome. For example, if you want to improve the conversion rate of your landing page, you can use experimental design to compare different versions of the page that vary in elements such as headline, layout, color, or call to action. By measuring and analyzing the results, you can determine which factors have the most impact on the conversion rate and how they interact with each other.

2 Why use experimental design?

Experimental design has several benefits for product development. First, it helps you reduce uncertainty and risk by providing evidence-based insights and feedback. Second, it helps you optimize your resources and time by focusing on the most relevant and influential factors and variables. Third, it helps you avoid biases and errors by following a rigorous and structured methodology that controls for confounding factors and random noise. Fourth, it helps you communicate and justify your decisions and recommendations by showing clear and quantifiable results and impacts.

3 How to use experimental design?

Experimental design involves several steps to identify and address an issue. First, you must define the problem and the objective. Then, you need to identify the factors and variables that could be causing the issue and the potential solutions or alternatives you want to test. Next, select an experimental design to arrange and manipulate the factors and variables. After that, execute the experiment by collecting and recording data. Afterward, analyze the results using statistical tools and techniques. Lastly, draw conclusions and recommendations based on the main findings of the experiment.

4 Types of experimental design

There are many types of experimental design, but they can be broadly classified into two categories: factorial and fractional. Factorial designs test all possible combinations of factors and variables, while fractional designs test only a subset of them. Factorial designs are more comprehensive and accurate, but they require more resources and time. Fractional designs are more efficient and economical, but they may miss some important interactions or effects.

One common type of factorial design is the A/B test, which compares two versions of a product or feature (A and B) on a single factor or variable. For example, you can test whether a green or a red button leads to more clicks on your website. A/B testing is simple and easy to implement, but it can only test one factor at a time and it may not account for other factors that affect the outcome.

One common type of fractional design is the Taguchi method, which uses a special matrix called an orthogonal array to select a subset of combinations that cover the most variation and interaction among the factors and variables. For example, you can test four factors (headline, layout, color, and call to action) with three levels each (high, medium, and low) using only nine experiments instead of 81. The Taguchi method is more complex and sophisticated, but it can test multiple factors at once and it can estimate the optimal levels and settings for each factor.

5 Best practices for experimental design

If you want to use experimental design effectively, it's important to start with a clear and specific research question and hypothesis. Additionally, you should choose the most relevant and influential factors and variables, as well as use a sample size that is large enough and representative of your target population. Randomizing and balancing your experimental conditions is also essential, as is controlling and monitoring external and internal factors that may affect the outcome. Furthermore, you should use appropriate statistical methods and tools to analyze and interpret your data, then report and communicate your results and recommendations clearly and convincingly. All of these steps are necessary for a successful experiment.

6 Examples of experimental design

Experimental design can be used to identify the root cause of a problem and many companies and industries have employed it in their operations. For example, Netflix used A/B testing to optimize its recommendation algorithm, Amazon used Taguchi method to improve its product packaging, and Airbnb used experimental design to improve its website design. All of these efforts led to increased user engagement and retention for Netflix, reduced damage rates and waste for Amazon, and increased user trust and conversion for Airbnb.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?