When reviewing the performance of a Google Ads account, a question I’m often asked is if the current impression share is good. In this short article, we’ll explore what impression share is, why you lose it, how you can gain it, and how to judge what’s good or bad.
What is impression share?
The official explanation from Google:
Impression share is the 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.
It’s a percentage indicator of your approximate market share for the traffic you’re targeting. If your impression share is 10%, your ad is showing one in every ten potential times. There are slightly different variations of it for search, display and shopping campaigns on Google Ads, but for the purposes of this article, we’ll generalize it as one thing.
Why do you lose impression share?
If your impression share is 10% and you’re missing out on 90%, there are two reasons why this may be the case – (1) ad rank, (2) budget. The lost impression share (Lost IS) may be for entirely one of the reasons, or more commonly a mixture of both.
Official explanations from Google:
Lost impression share (rank) estimates how often your ad didn’t show due to poor Ad Rank.
Lost impression share (budget) estimates how often your ad didn’t show due to a low budget.
Lost impression share to ad rank: Google is holding back potential traffic from you because it doesn’t like something about your quality score, your bidding, or both. In layman’s terms, it’s extortion, punishment, or both. Ad rank = quality score x bid. If your quality scores are good (a rating system out of ten in relation to your CTR, relevance and landing page), it likely means you need to bid more to increase your rank and therefore unlock the withheld impressions.
Lost impression share to budget: If you increase your daily Google Ads budget you’ll be granted access to the withheld impressions. For example, if your current IS is 50% and your IS lost budget is 50%, it means you need to double your budget if you want to get the rest of the available traffic.
Note: it’s very unusual to achieve a 100% impression share.
Is your impression share good or bad?
IS = Impression Share
The above screenshot shows an IS of 89.42% with 3.00% lost to rank and 7.58% lost to budget. In this case, it’s hard to say the IS is not ‘good’ – it’s very high with a minimal amount lost to rank especially.
Whether your IS is good or bad is entirely dependent on the size of your addressable audience and its relativity to your objectives.
One could argue that if your IS is 5% in a HUGE market with millions of searches per day, then your 5% portion is significant and enables you to generate enough leads or sales to meet your business growth objectives. Equally, in a smaller market with less available traffic, you could have an IS of 65% which is not enough leads, sales or traffic for you. This is why I liken impression share to market share. This is why you can’t look at IS in isolation.
Regardless of how much IS you’re losing, you generally want most of that ‘loss’ to be due to budget, not due to rank. If you’re losing 90% IS and 85% of it is due to rank, it means even if you increased your budget to $1bn per day you’re not going to get that missing 85% IS until you fix your rank issues (bidding or quality score).
I hope this helps you to understand what impression share is, why you’re losing it and how to evaluate yours. Thanks for reading!