How can we optimize a Performance Max campaign with a sharp performance drop this month, compared to last month?
We can do the following:
Check the Listing Groups, product-wise. Has a well-performing product gone out of stock? Have there been any major spend/CTR/conversions changes w.r.t. a particular product?
Refresh the audience signals; add more keywords to the custom intent audiences and refresh the first-person remarketing lists (offline purchasers, general customer data, all-time organic purchasers data)
Check the Placements Report. Are a large number of impressions going to a particular website/app, relative to the previous period?
Check if a particular location has had disproportionate spends, or there has been a disproportionate drop in the conversion rate. Exclude locations/increase midfunnel marketing accordingly.
Check Insights tab to see changes in demand/rising queries/falling queries. Optimize these by adding them to your Custom Intent audiences.
After working on catalog titles, bidding strategy, and audience signals, what further can we do to optimize performance?
We can add sitelink extensions, edit feed attributes in the Google Merchant Center, add Merchant Promotions and Product Review feeds, both in the Google Merchant Center.
How can we analyze the reasons for abrupt overspend in Performance Max campaigns?
We can check which Listing Groups, if any, suddenly increased in spends, and take action. We can also check the Placement Report.