Meta ad set performance

Ad-set level results with the objective's own KPI and a previous-period comparison, optionally split by a breakdown (age and gender, publisher platform and position, device, or country). Use when: one campaign is under- or over-performing and you need to know which audience or placement is responsible. Do not use with a breakdown to judge overall performance — breakdown rows do not sum to the campaign total for every metric, and some metrics are unavailable when a breakdown is applied. Returns each ad set's spend, results, cost per result and ROAS where the objective supports it. If the user asks "why is this campaign expensive", run this with the placement breakdown before recommending anything.