Rising cost with a frequency near 3 could be fatigue, or a budget, audience or offer change. I can't tell from one frequency figure, and Meta's pages give no frequency number where fatigue starts, so 3 on its own does not answer it. To compare each ad with its own early weeks, I need three things:
- Weekly rows per ad: ad name, week, impressions, reach, results and amount spent. Reach is the key one: frequency is impressions divided by reach, and cost per result is spend divided by results, so I compute both per week instead of using an average.
- Ad set details per ad: the ad set name, how many creatives the ad set holds, and the current Delivery column status. Meta shows its Creative limited and Creative fatigue statuses only for ad sets with one creative, so for larger ad sets I rely on your rows.
- What a result is: purchase, lead or something else, so the cost per result means the same thing in every row.
Optional: how many first weeks count as each ad's baseline. My default is the first 2 weeks, labeled.
Also useful: did budget, audience or the offer change in the same weeks? Those are questions I'll ask, not causes I'll assume.
Source for the statuses: https://www.facebook.com/business/help/1346816142327858
I won't pause, edit or launch any ad. Any test I suggest stays held for your approval.