CRO Optimizer

My best CRO win was +25%. The retest said minus 14%. Nothing had broken. Both numbers were real. I had simply treated a single run as a fact, written it into the baseline, and let every decision after that stand on it. That is the failure this skill exists to stop. cro-optimizer is the third skill in my CRO chain. cro-audit finds what is broken, cro-actions plans the fix, and this one reads the outcome after it ships and decides whether the result survives. Two gates run on every result: a significance gate (sig floor, duration, power against a declared MDE, peeking, thin samples) and a causal-overreach gate (discount applied, no certainty language, stable estimate, confounds checked, guardrail metric named). Both must pass, every time. The numbers behind those rules: about half of all tests are statistically null, peeking pushes a 5% false-positive rate to 26%, and test wins overstate production by 20-50%. So the lift that reaches your baseline is discounted, and it is smaller than the one in the deck. Worked example: a pricing test returns +18%. Provenance is read from the deploy log, both gates pass, the guardrail is flat, and the verdict is won at a projected +9-14% in production. Run the same call on day 3 and the answer is inconclusive, because 3 days is not 7 and the test was peeked. Guidance-only. 18 evidence cards, 6 references, 5 recipes, 12 learnings, 2 scripts, zero methods. PostHog and GA4 measure, SpiderPublish deploys and rolls back, and this skill decides between them.