Want to know if A beats B? First ask if doing A changes how you do B (or vice versa)? If the answer is “Yes”, use different people for each. Give one group A, the other B, and measure the same outcome once. That’s an independent two-sample comparison. No memory effects. No practice carryover. Just a cleaner answer. Compare the averages and ask: “Is the gap big enough to matter, and unlikely to be luck?” Statistics won’t tell you what to want; it tells you if what you’re seeing is probably real. The principle scales… from training plans to onboarding paths to landing pages. Two groups. Fair test. Clear decision.
