The percentage of eligible search auctions in which an ad actually appeared. Lost impression share is reported by cause: budget (the campaign ran out of money) or rank (the bid or Quality Score was too low). Impression share on brand terms is the standard defensive metric; on non-brand terms it indicates headroom.
Related terms
Used in The Signal
- Google Ads vs. Meta Ads Is Not a Rivalry. It Is a Relay.
- Google Is Migrating Your Search Campaigns This Month. Set the Baseline Before It Does.
- Impression Share Is the Only Auction Metric That Tells You About the Auction
- PPC Works in Weeks and Compounds in Quarters
- Share of Voice Buys Market Share on a Delay
Cite this entry:
Agency Echelon. "Impression Share." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/impression-share/