Representative samples and generalizability of A/B testing results

I see a nice trend in recent discussions on A/B testing: more and more people realize the need for proper statistical design and analysis which is a topic I hold dear as I’ve written dozens of articles and a few white-papers on. However, there ar…

I see a nice trend in recent discussions on A/B testing: more and more people realize the need for proper statistical design and analysis which is a topic I hold dear as I’ve written dozens of articles and a few white-papers on. However, there are cases in which statistical validity is discussed without consideration for […] Read More...

Designing successful A/B tests in Email Marketing

The process of A/B testing (a.k.a. online controlled experiments) is well-established in conversion rate optimization for all kinds of online properties and is widely used by e-commerce websites. On this blog I have already written in depth about the s…

The process of A/B testing (a.k.a. online controlled experiments) is well-established in conversion rate optimization for all kinds of online properties and is widely used by e-commerce websites. On this blog I have already written in depth about the statistics involved as well as the ROI calculations in terms of balancing risk and reward for […] Read More...

Website quality assurance: How to make certain your experiments don’t fail before they launch

According to Donald Norman, the user’s final experience of your website is at a reflective level: Was the experience delightful…Read blog postabout:Website quality assurance: How to make certain your experiments don’t fail before they launch
The post…

According to Donald Norman, the user’s final experience of your website is at a reflective level: Was the experience delightful...Read blog postabout:Website quality assurance: How to make certain your experiments don’t fail before they launch

The post Website quality assurance: How to make certain your experiments don’t fail before they launch appeared first on WiderFunnel Conversion Optimization.

Analysis of 115 A/B Tests: Average Lift is 4%, Most Lack Statistical Power

What can you learn from 115 publicly available A/B tests? Usually, not much, since in most cases you would be looking at case studies with very basic data about what was tested and the outcome of the A/B test. Confidence intervals, p-values and other m…

What can you learn from 115 publicly available A/B tests? Usually, not much, since in most cases you would be looking at case studies with very basic data about what was tested and the outcome of the A/B test. Confidence intervals, p-values and other measurements of uncertainty will often be missing, and when present they […] Read More...

Confidence Intervals & P-values for Percent Change / Relative Difference

In many controlled experiments, including online controlled experiments (a.k.a. A/B tests) the result of interest and hence the inference made is about the relative difference between the control and treatment group. In A/B testing as part of conversio…

In many controlled experiments, including online controlled experiments (a.k.a. A/B tests) the result of interest and hence the inference made is about the relative difference between the control and treatment group. In A/B testing as part of conversion rate optimization and in marketing experiments in general we use the term “percent lift” (“percentage lift”) while in […] Read More...

Affordable A/B Tests: Google Optimize & AGILE A/B Testing

The problem most-often faced by owners of websites who want to take a scientific approach to improving them by using A/B testing is that they might have relatively small revenue. Thus, when the ROI calculation for the A/B test is done it might turn out…

The problem most-often faced by owners of websites who want to take a scientific approach to improving them by using A/B testing is that they might have relatively small revenue. Thus, when the ROI calculation for the A/B test is done it might turn out that it is economically unfeasible to test. In some cases, […] Read More...

The Google Optimize Statistical Engine and Approach

Google Optimize is the latest attempt from Google to deliver an A/B testing product. Previously we had “Google Website Optimizer”, then we had “Content Experiments” within Google Analytics, and now we have the latest iteration: …

Google Optimize is the latest attempt from Google to deliver an A/B testing product. Previously we had “Google Website Optimizer”, then we had “Content Experiments” within Google Analytics, and now we have the latest iteration: Google Optimize. While working on the integration of our A/B Testing Calculator with Google Optimize I was curious to see […] Read More...

Bayesian vs Frequentist A/B Testing – What’s the Difference?

Bayesian versus Frequentist Statisticians: the war is real
Imagine that you wake up in the one morning and you don’t remember anything from your previous life. You’ve erased all memories from…

Please click on the title to read the full articl…

Bayesian versus Frequentist Statisticians: the war is real Imagine that you wake up in the one morning and you don’t remember anything from your previous life. You’ve erased all memories from...

Please click on the title to read the full article!

20-80% Faster A/B Tests? Is it real?

I got a question today about our AGILE A/B testing calculator and the statistics behind it and realized that I’m yet to write a dedicated post explaining the efficiency gains from using the method in more detail. This despite the fact that these …

I got a question today about our AGILE A/B testing calculator and the statistics behind it and realized that I’m yet to write a dedicated post explaining the efficiency gains from using the method in more detail. This despite the fact that these speed gains are clearly communicated and verified through simulation results presented in our AGILE […] Read More...

Risk vs. Reward in A/B Tests: A/B testing as Risk Management

What is the goal of A/B testing? How long should I run a test for? Is it better to run many quick tests, or one long one? How do I know when is a good time to stop testing? How do I choose the significance threshold for a test? Is there something speci…

What is the goal of A/B testing? How long should I run a test for? Is it better to run many quick tests, or one long one? How do I know when is a good time to stop testing? How do I choose the significance threshold for a test? Is there something special about 95%? […] Read More...