Martin Goodson - Most Winning A/B Test Results are Illusory
http://youtu.be/MdkHLS0FPMk
Related to inflation of Type 1 error (false positives) through multiple comparisons (Post-hoc Tests)
also see www.goo.gl/jvhwmB
How to avoid these common pitfalls? See this resource:
Testing 1-2-3 Experimental Design in Marketing and Service (Ledolter)