A must-read paper on statistical analysis of experimental data

Russ Lyons points to an excellent article on statistical experimentation by Ron Kohavi, Alex Deng, Brian Frasca, Roger Longbotham, Toby Walker, Ya Xu, a group of software engineers (I presume) at Microsoft. Kohavi et al. write: Online controlled experiments are often utilized to make data-driven decisions at Amazon, Microsoft . . . deployment and mining [...]