Company
Date Published
Author
Ravi Parikh
Word count
1094
Language
English
Hacker News points
None

Summary

A/B testing in website design is analogous to drug trials in pharmaceuticals, as both involve comparing a test group to a control group to validate effectiveness. Just as premature stopping in drug trials can lead to false positives, ending A/B tests early can result in inaccurate conclusions about changes improving conversion rates. The article illustrates this through a real-world example where an early assessment led to a false positive result, which was corrected after letting the test run its full course. It emphasizes the importance of adhering to statistical guidelines, such as not stopping tests prematurely, to avoid skewing results and increasing the false positive rate. Simulations demonstrate that frequent monitoring and stopping tests at the first sign of significance can dramatically inflate the false positive rate, rendering the test unreliable. The solution is to allow tests to run their full course or apply more complex statistical methods if early stopping is necessary.