Google defines Impression share (IS) as the percentage of impressions an ad receives to the total number of impressions that an ad could get.
The definition is self-explanatory. But how can you calculate your Impression share? What are the types of Impression share? And what are its implications? We will discuss all that in this blog.
Impression share (IS) calculation –
(IS) = Impressions received / Total eligible impressions
Google uses this formula to calculate the Impression share. Google estimated eligible impressions using many factors, including targeting settings, approval statuses, and quality. Impression share data is available for campaigns, ad groups, product groups (for shopping campaigns), and keywords. Usually this data has a time lag of 2 to 3 days and will only be shown for campaigns/ad groups/keywords with significant impressions.
Types of Impression Share (IS) in AdWords –
- Search IS – (IS) only for impressions generated through Search Network.
- Display IS – (IS) only for impressions generated through Display Network.
- Search Lost IS (budget) – The percentage of impressions lost out on Search Network due to insufficient budget.
- Display Lost IS (budget) – The percentage of impressions lost out on Display Network due to insufficient budget.
- Search Lost IS (rank) – The percentage of impressions lost out on Search Network due to low ad rank.
- Display Lost IS (rank) – The percentage of impressions lost out on Display Network due to low ad rank.
- Search Exact Match IS – (IS) from Search Network for search queries that matched keywords exactly.
Note: Lost (IS) due to low budget is available only at the campaign level.
Implications of Impression Share (IS) –
Impression share gives us an idea on how bidding high on a keyword or increasing the budget of a campaign improves the visibility of ads.
If keyword bids are low, the risk of not winning an ad space on the first SERP is inevitable. And this might put you in a position where you are losing impressions, clicks, and conversions. This isn’t good for your business. Using Average Position metric of keywords along with Impression share, you can understand what has gone wrong. The Average Position is good, but the share of impressions is low. Your ads are not getting the kind of exposure that is supposed to be at such high positions.
Likewise, Google doesn’t show your ads if your daily budget gets exhausted. The budget is low, and it gets exhausted by mid-day. You are missing out on impressions for the rest of the day. And for very obvious reasons, it isn’t a good practice. We highly recommend our advertisers to reduce Impression share lost due to budget (preferably zero)
How does Google estimate Impression share?
Google monitors the auctions over the course of a day. Google uses internal information such as quality for you and all other participants in the same ad auctions. Impression share includes all auctions where your ad showed and all auctions where your ad is competitive enough to show. Google estimates IS based on when your ad was competitive in the auction. You don’t need to worry when there are small fluctuations. Changes to your bids, quality, or Google’s ad systems may change the set of auctions in which the system estimates you were competitive. Google could include auctions where your ad could show at twice its current bid. But Google could also exclude auctions where your ad needs a 1,000% bid increase in order to appear.
Impression share estimation for Shopping Ads –
Google calculates IS for Shopping campaigns similarly to text ads. However, Google considers that multiple Shopping ads from the same advertiser can show at the same time. And in order to avoid double counting when multiple ads from the same advertiser are in the same auction, AdWords assigns the impression and the impression opportunity to the highest ranked Shopping ad from that advertiser.
Besides the budget and bid, quality of the ad copy and geotargeting setting also impact the Impression share. Lesser restriction on targeting and improved ad copy quality can boost the share of impressions.
Where to find the Impression share data in AdWords?
You can find the IS data under the Columns button in AdWords. You have to choose “customize columns”, then “competitive metrics”, where all of the different Impression share metrics are available.