IS: Impression Share
The percentage of eligible impressions your ads received out of the total impressions they could have received.
Formula
Why it matters
Impression Share reveals budget constraints and competitive pressure. Low IS due to budget means you are leaving impressions on the table — more budget would capture more relevant clicks. Low IS due to rank means Quality Score or bid improvements are needed.
How to improve IS
For budget-limited IS: increase daily budget. For rank-limited IS: improve Quality Score or increase bids. Focus on high-converting campaigns first.
Search campaigns: 70–90% is strong for branded terms. 30–60% is typical for competitive non-branded terms.
Prooflytics tracks IS automatically from your connected sources and flags it in your daily briefing when it moves significantly.
Start free trialFrequently asked questions
What is lost IS (budget) vs lost IS (rank)?
Lost IS (budget) is the share of impressions you missed because your daily budget ran out. Lost IS (rank) is the share you missed because your bid and Quality Score combination wasn't high enough to win the auction.