A pacing throttle was silently capping win rate at 14% mid-flight

A pacing throttle was silently capping win rate at 14% mid-flight

A campaign with healthy bids kept stalling at low win rate. The cause was the pacing engine, not the auction.

Pacing (the DSP's logic that spreads budget evenly across a flight by throttling how many auctions you enter per hour).

1. They overlaid hourly win rate against the pacing engine's bid-throttle rate from log-level data.
— Whenever the throttle exceeded 60%, win rate dropped from 24% to 14%.
2. The throttle was set to ASAP-smoothed, but a low daily cap made it skip most morning auctions to reserve budget for the day.
3. They raised the daily cap 40% and switched pacing to even-with-front-load.

Evidence: skip rate fell from 61% to 22%, and effective win rate on entered auctions recovered to 23%. The bids had been competitive all along; the engine was declining to enter most auctions, so the campaign looked uncompetitive when it was simply absent.

Why it matters: win rate is only measured on auctions you actually enter. A throttling pacer can make a winning bid look like a losing one by keeping it out of the room. Separate skip rate from loss rate before touching the bid.