When a test has run long enough to reach significance, end it and implement the winner - PDQ can apply it for you.
Step 1: End the test
In Optimize → A/B Tests → Running, click ⋯ → End Test. The test moves to Concluded.
Step 2: Review the results
Open the results (Concluded → ⋯ → Get Analytics, or the Analytics Dashboard). Review the goal metric, the lift, and statistical significance per variant and segment. You can add a comment/summary to the test for your records.
Step 3: Implement the winner
From the End Test / results window, select the winning variant (or winning segment) to roll it out:
Shipping Rates / Checkout Group tests - the winning group's rules are frozen into a segment and applied going forward.
Cross-Site (Theme) tests - select the winning theme; traffic auto-routes to it. ⚠️ Don't delete the losing variant theme before selecting a winner.
Extensions / Extension Groups - keep the winning extension/stack live and remove the losing token.
Tip: implement based on significance, not just raw lift - a higher number that isn't significant isn't a reliable win.