As a presenter on our recent technology-focused web clinic, I had the pleasure of learning about an experiment devised by my colleague, Jon Powell, that illustrates why we must never assume that we test in a vacuum devoid of any external factors that can skew data in our tests (and even looking at external factors that we can create ourselves).
If you’d like to learn most about this experiment in its entirety, you can hear it firsthand from Jon on the web clinic replay. SPOILER ALERT: If you choose to keep reading, be warned that I am now giving away the ending.
According to the testing platform Jon was using, the aggregate results came up inconclusive. None of the treatments outperformed the control with any significance difference. However, what was interesting is the data indicated a pretty large difference in performance with a couple of the treatments.
So after reanalyzing the data and adjusting the test duration to exclude the results from when an unintended (by our researchers at least) promotional email had been sent out, Jon saw that each of the treatments significantly outperformed the control with conclusive validity.
In other words, if Jon had blindly trusted his testing tool, he would have missed a 31% gain. Even worse, this gain was at the beginning of a six-month-long testing-optimization cycle. If Jon had assumed he had learned something based on inaccurate data that he really hadn’t, this conclusion more than likely would have sent Jon down a path of optimizing under false findings and assumptions.
In other words, to create a simple pre-GPS era analogy, if you make a wrong turn at the beginning of a 600-mile road trip and keep heading in the wrong direction, you will be much farther off the mark than taking the wrong road when you’re just a mile away. However, in our cases with many businesses, wrong turns and mis-directions can cost from thousands to millions of dollars in lost time and revenue.
Worst of all, this email came from the Research Partner itself. As we run into many times, they unwittingly sabotaged their own tests. With the Internet being a dynamic place, it is next to impossible to avoid every external validity threat to your test, but at the very least we need to make sure that we are not introducing threats with internal campaigns to the same audience.
This is not to say we stop those campaigns, but just be aware of the potential effects on testing. That awareness, at least until computers become sentient beings, requires human involvement. Of course, that’s just one area where a little human curiosity is essential… Read more…