The Paid Media Waste Finder compares each campaign or ad set against your account's own performance medians — cost-per-acquisition, click-through rate and spend-to-conversion ratio — and flags line items that are burning budget well below those benchmarks with little to show for it. It also separately flags creative fatigue (high frequency, falling CTR) and scaling candidates (performance well above the median that could absorb more budget).
Because the benchmark is your own account, not an industry average, the flags reflect what is actually underperforming for you, not a generic rule of thumb.