Published September 7, 2026.
An experiment without a stop rule tends to end when the result feels exciting or uncomfortable. Write the rule before making the change.
Define one decision
State the page set, intervention, primary observation, comparison period, and minimum run window. Note concurrent releases, seasonality, and data thresholds that could make interpretation unreliable.
Name safety stops
Pause immediately for broken routes, incorrect canonicals, misleading claims, accessibility regressions, or material conversion defects. These are quality failures, not acceptable experimental variance.
Separate observation from causation
Search performance can change for many reasons. Record what moved and what else changed. Use the result to inform the next decision without claiming the intervention caused an outcome unless the design supports that conclusion.
The analyst collects data and applies the prewritten rule. The content owner approves strategic conclusions and any broad rollout. A one-page card makes experimentation compatible with a disciplined daily publishing routine.