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Chapter 3: Understanding Your QPS Funnel

Audience: media buyers, campaign managers

This is the home page of Cat-Scan (/). Everything starts here.

What you see

The QPS Waste Optimizer page shows your RTB funnel (the journey from bid request to spend) and highlights where volume drops off.

QPS Waste Optimizer home page

The funnel

Stage What it means
QPS The maximum bid requests per second you ask Google to send. Google throttles the actual volume based on your account tier, so you typically receive less than your cap.
Bids How many of those requests your bidder chose to bid on. The rest were rejected (wrong inventory, no matching creative, below floor price).
Wins Auctions your bidder won. You only pay for wins.
Impressions Ads actually served to users after winning.
Clicks User interactions with your served ads.
Spend Total money spent on won impressions.

The gap between each stage is where optimization opportunity lives. A large drop from QPS to Bids means your bidder is rejecting most of what Google sends, classic waste that pretargeting can fix.

Key metrics

  • Win rate: Wins / Bids. How competitive your bids are.
  • CTR: Clicks / Impressions. How engaging your creatives are.
  • CPM: Cost per thousand impressions. What you're paying for visibility.
  • Waste ratio: (QPS - Bids) / QPS. The fraction of traffic you can't use.

Pretargeting config cards

Below the funnel, you'll see cards for each of your pretargeting configurations (up to 10 per seat). Each card shows:

  • State: Active or Suspended
  • Max QPS: The cap on bid requests this config accepts
  • Formats: VIDEO, DISPLAY_IMAGE, DISPLAY_HTML, NATIVE
  • Platforms: DESKTOP, MOBILE_APP, MOBILE_WEB, CONNECTED_TV
  • Geos: Included and excluded geographic targets
  • Sizes: Included ad sizes (or all if unfiltered)

Controls

  • Period selector: 7, 14, or 30 days of data
  • Seat filter: scope to a specific buyer seat
  • Config toggle: drill into a specific pretargeting config

How to read it

Start with the waste ratio. If it's above 50%, you have significant room to improve. Then look at which configs contribute the most waste. Click into the dimension analyses (Geo, Publisher, Size) to find the specific sources.