Google Ads Impression Share (IS) is the percentage of impressions that your ads get in comparison with the total number of impressions that your ads could have been eligible to get. In terms of mathematics, it can be expressed as:
Impression share = impressions / total eligible impressions
So, what are Eligible Impressions then?
Google estimates Eligible Impressions for your ads based on several factors. Some of the key factors are:
- Targeting settings,
- Approval statuses,
- And, of course, quality.
You can check the Impression Share data at campaigns, ad groups, product groups, and keywords levels. Product groups are applicable in the case of shopping campaigns only.
What is Absolute Top Impression Share?
Absolute Top Impression Share (ATIS) is a key metric for Shopping Campaigns. As you know Google shows several shopping ads for a particular search query. The ad that shows at the absolute top, or say, the first ad in shopping ads block on the search result page is the absolute top position for the ad. Every impression that your ad gets at this position is the absolute top impression. And, the percentage of impressions that your shopping ads get at this position is the Absolute Top Impression share. The formula for ATIS is:
Absolute top impression share = absolute top impressions / total eligible top impressions
It is also important to note that every auction can have only one Absolute Top Impression.
Other key metrics for Impression Share
Display impression share: The number of impressions your ads have received divided by the estimated number of impressions your ads were eligible to receive on the Display Network.
Search Lost IS (budget): As it is already indicated by the name, this metric relates to your campaign budget. The percentage of time that your ads could not be shown on the Search Network because of an insufficient budget is called the Search Lost IS (budget). You can check this metric only at the campaign level.
Display Lost IS (budget): The percentage of time that your ads could not be shown on the Display Network due to an insufficient budget is termed as Display Lost IS (budget). This metric as well is available only at the campaign level of your display network campaigns.
Search Lost IS (rank): This metric relates the bids and quality score, precisely ad rank, of your ads. The percentage of time that your ads could not be shown on the Search Network because of a bad Ad Rank in the auction is called Search Lost IS (rank).
Display Lost IS (rank): Same as the Search Lost IS (rank), this metric is the percentage of time that your ads could not be shown on the Display Network because of a poor Ad Rank.
It is also important to note that Lost IS (rank), whether for Search or Display campaigns, won’t be available at the Ad groups level if your campaign was limited by budget during/in the period you are trying to check this metric for.
Search Exact match IS: This metric is available only for Search Network campaigns. The impressions your ads have got divided by the estimated number of impressions your ads were eligible to get on the Search Network for search terms that matched your keywords in the Exact Match is called the Search Exact Match Impression Share.
Learn how to improve your Google Ads impression share.