How can you separate correlation from causation when diagnosing?

Avoiding false conclusions in diagnosis:

Correlation trap: "We changed the subject line AND deliverability dropped" does not prove causation.

Establish timeline: Did the suspected cause happen before the effect?

Isolate variables: Test one change at a time when possible.

Look for alternative explanations: What else changed? Provider updates? List composition?

Check consistency: Does the problem occur every time that condition exists?

Reproduce: Can you trigger the problem by recreating the suspected cause?

External validation: Are other senders experiencing similar issues?

Misdiagnosis wastes time and may make things worse. Verify before acting.

The storm and the engine failure happened the same day. Only one caused the shipwreck.