Advertising
Impression Share
Impression share is the percentage of total available impressions your ads received compared to the total they were eligible to receive. It indicates how much of the potential market your campaigns are capturing.
Examples
A search campaign with an impression share of 72% means the ads appeared in 72% of the auctions they were eligible for.
Best Practices
Monitor impression share by campaign and keyword, and investigate whether budget or rank is limiting your share of available impressions.