What is Placement Leakage?

Placement Leakage is ad budget draining into junk inventory — mobile game apps, low-quality websites, and irrelevant YouTube channels — where impressions accumulate but nobody is shopping.

Why it matters

Performance Max and Display campaigns choose placements automatically and report them in places most advertisers never look. Mobile app placements are the classic case: taps are often accidental, and the algorithm keeps routing budget there because impressions and clicks look like engagement.

How ClickCatalyst detects it

ClickCatalyst counts every impression across PMax, Standard Display, and Video placement tables, then calculates the percentage that appeared inside mobile apps — the single number that quantifies junk exposure.

Exclusion candidates are placements with more than 500 impressions and zero conversions — each one is a copy-paste entry for the account exclusion list.

Because PMax does not report per-placement cost, cost is estimated with a CPM proxy: the account's average cost per 1,000 impressions multiplied by each placement's impression count. A trend line of app impressions versus everything else shows whether the algorithm is routing more budget to junk over time.

mobile_app_share = app_impressions ÷ total_impressions × 100

Exclusion candidate: impressions > 500 AND conversions = 0

placement_cost ≈ (SUM(cost) ÷ SUM(impressions) × 1000)
                 × placement_impressions   // CPM proxy

Example

One audit found 63% of a PMax campaign's placement impressions landing on mobile game apps like "Toddler Games Free" and "Candy Match 3" — 41,087 junk impressions blocked after exclusion.