the devs at thumbtack.com maintain a blog w/ 2-3 excellent posts on the subject. i liked these because the authors clearly have experience in all three aspects

the devs at thumbtack.com maintain a blog w/ 2-3 excellent posts on the subject. i liked these because the authors clearly have experience in all three aspects of split-path testing: (i) the engineering (how to implement? eg, via template-switching middleware); (ii) the analysis (probability theory); (iii) test config--identifying orthogonal features suitable to test. so there's that plus the app they use. Of all the A/B-test metrics apps i know of that are named in honor of 1980's bands, thumbtack's has the best name, "ABBA"