Mistakes in Experimental Design and Interpretation is a nice exposition of the pitfalls you may see when you perform experiments. Remember: any time you measure performance of your code, you are doing an experiment on your system, so the aforementioned caveats apply.
Re:Conan Doyle out-sherlocked by Sherlock
Mark Leighton Fisher on 2007-07-13T16:20:46
"Clinical judgement is no substitute for rigorous measurement--and vice versa." I like that – clear thinking and clear measuring.