Impression share compares what you actually got with what was available to you. Google reports it with two reasons for whatever you missed: share lost to budget, and share lost to rank. Together they answer a question most advertisers otherwise guess at — whether spending more would actually change anything.
Briefly explained
- How much of the available demand you actually captured.
- Lost to budget: the money stopped before the demand did.
- Lost to rank: you turned up to the auction and came second.
- 100% is almost never the right target.
How do the two loss columns differ?
They point at completely different fixes.
- Lost to budget: You were eligible and would have won, but the day’s money was already gone. The constraint is money.
- Lost to rank: You entered the auction and were beaten. Bid and relevance were not enough. The constraint is the account.
Raising the budget fixes the first and barely touches the second. It is the most common mistake made with this report.
How should you act on it?
In this order, which keeps you from buying more of something unprofitable.
- Check profitability per campaign first, using cost per booked job rather than cost per click.
- On profitable campaigns losing to budget, raise it in steps and re-check after a week.
- On campaigns losing to rank, look at Quality Score components and the landing page before touching bids.
- On campaigns that are not profitable, do nothing to the budget at all.
Why is 100% the wrong goal?
Because impressions are not equally valuable. The share you are missing is usually the loosest end of the matching: the searches where you were a weak fit, at the hours when buyers are scarce, in the places you half cover.
Buying it raises average cost and lowers average quality at the same time. A campaign at 55% share on the right searches beats one at 90% on everything.
What moves it that has nothing to do with you?
Seasons and competitors.
A share that falls in a busy month usually means the auction filled up, not that something broke. The useful comparison is the same month last year, which is also the point of year over year.
What do the terms mean?
- Impression share: What you got, set against what was there to get.
- Lost to budget: What went elsewhere once the daily budget was gone.
- Lost to rank: What you gave up by being outranked.
- Top impression share: The equivalent figure for the positions at the top of the page.
- Eligible impressions: Google’s estimate of how often you could have shown, given your targeting.
Owner questions
