Impression share (IS) is the number of impressions you’ve received divided by the estimated number of impressions you were eligible to receive. Eligibility is based on your current ads’ targeting settings, approval statuses, bids, and Quality Scores. Data is available at the campaign, ad group and keyword levels.
An easy way to understand the value of impression share is to think of the online advertising landscape as a delicious pie. You and your competitors are each trying to grab the biggest slice of that pie. By tracking your impression share metrics, you’re keeping tabs on the size of your slice compared to the whole.
If your keyword bids are too low, you might risk your ads not appearing on the first page, which may lead to missed opportunities for impressions, clicks, and even conversions. Ensuring that your bids are high enough that your ads are appearing in competitive positions will greatly improve your chances of capturing impressions and clicks, and generating traffic to your site. You will definitely want to use this metric in conjunction with the average position of your keywords. You may notice that the average position for your keywords is high, but that your impression share is low. This can tell you that when your ads appear, they appear in high positions, but because your impression share is low, those ads aren’t getting as much exposure as they could be in those high positions.
Available network-specific impression share metrics include:
- Search impression share: The impressions you’ve received on the Search Network divided by the estimated number of impressions you were eligible to receive.
- Display impression share: The impressions you’ve received on the Display Network divided by the estimated number of impressions you were eligible to receive.
- Search Lost IS (budget): The percentage of time that your ads weren’t shown on the Search Network due to insufficient budget. This data is available at the campaign level only.
- Display Lost IS (budget): The percentage of time that your ads weren’t shown on the Display Network due to insufficient budget. This data is available at the campaign level only.
- Search Lost IS (rank): The percentage of time that your ads weren’t shown on the Search Network due to poor Ad Rank. Note: Lost IS (rank) won’t be shown on your Ad groups tab if you ran out of budget at any point during the date range being examined.
- Display Lost IS (rank): The percentage of time that your ads weren’t shown on the Display Network due to poor Ad Rank. Note: Lost IS (rank) won’t be shown on your Ad groups tab if you ran out of budget at any point during the date range being examined.
- Search Exact match IS: The impressions you’ve received divided by the estimated number of impressions you were eligible to receive on the Search Network for search terms that matched your keywords exactly (or were close variants of your keyword).