| CPC/CPM up, CVR and AOV stable | Auction cost | Acquisition cost | Review competition, channel economics and bidding constraints |
| Click response down | Creative or ad relevance | Traffic generation | Diagnose message, creative and query or audience fit |
| Clicks stable, purchases down | Traffic quality or store CVR | Conversion | Find the weak store funnel stage |
| Purchases stable, ROAS down | AOV / order-value mix | Value | Analyze basket and product mix |
| Revenue up, contribution down | Discount, margin or product mix | Economics | Use contribution guardrails |
| Google weak, Meta healthy | Intent, feed or value bidding | Google channel | Use Google diagnostic branches |
| Meta weak, Google healthy | Creative, audience or value optimization | Meta channel | Use Meta branch |
| Both Google and Meta decline | Store, economy, seasonality or measurement | Shared system | Check shared causes first |
| Brand excellent, prospecting weak | Funnel role | Demand capture vs creation | Do not compare directly |
| All-customer good, new-customer weak | Customer mix | Acquisition | Separate new and returning revenue |
| Platform ROAS improves, MER worsens | Attribution or blended system | Measurement | Check overlap and total marketing efficiency |
| ROAS falls after scaling | Marginal return | Scale | Evaluate next-unit economics |
| ROAS very high but spend tiny | Possible under-scaling | Scale | Test whether lower marginal return creates more contribution |
| PMax weak on specific SKUs | Feed and product economics | Product | Analyze SKU, category and margin |
| Meta catalog weak on some products | Catalog and product value | Product | Analyze mix, price, creative and product page |
| High ROAS with high returns | Gross revenue quality | Economics | Use net revenue or contribution where possible |