Start with a comparison window
Choose comparable dates, objectives, placements, and audiences. A change in frequency or CPA is not useful evidence if the underlying mix also changed.
Review delivery, impressions, frequency, click or response rate, landing behavior, outcomes, and CPA together. No single metric proves fatigue.
A hypothetical diagnosis
Hypothetical example: frequency rises from 1.8 to 3.2 while response rate falls, but the landing page also changed. Separate the creative question from the landing-page question before assigning a fatigue label.
Prepare one bounded test
Select one variable such as hook, first frame, proof format, offer framing, or landing-page message. Record the hypothesis and keep the human decision visible. This checklist is not Meta-certified and does not use Meta's private algorithm.