Impression share

Impression share is the proportion of the times your advert could have appeared that it did appear. Google Ads divides the impressions you received by its estimate of the impressions you were eligible to receive, and reports the result as a percentage.

In short

• Impressions received divided by impressions you were eligible for.
• The denominator is Google’s estimate, so read it as approximate.
• The two lost columns, budget and rank, carry the diagnosis.
• High is not the goal. Knowing why you are missing the rest is.

The columns and what they separate

The headline figure is the least useful number in the set. What it is worth opening is the pair beneath it.

• Search impression share. What you got, out of what you could have got.
• Search lost IS (budget). The share you missed because the campaign stopped spending. Reported where budgets live, which is the campaign.
• Search lost IS (rank). The share you missed because your Ad Rank was not high enough to win the auction.
• Search exact match IS. The same calculation limited to searches that matched your keyword exactly.
• Top and absolute top impression share. Not how often you appeared, but how often you appeared above the results and in the very first position.
• Display equivalents. The same set for the Display Network.

The three shares add up. If you have thirty per cent and you lost fifty to rank, you lost the remaining twenty to budget, and the two numbers together describe the whole picture where the first one alone describes almost nothing.

Budget and rank point in opposite directions

This is the entire practical value of the metric, and it is why the split is worth checking before any other diagnostic in a Google Ads account.

Losing to budget means you stopped. The campaign spent what it had, went quiet, and searches carried on happening without you. There is nothing wrong with the advertising itself. Either the budget rises, or the targeting narrows so the same budget covers a smaller and better defined set of searches, usually by adding negative keywords.

Losing to rank means you were there and did not win. Ad Rank combines your bid with the quality of the advert and landing page, the context of the search and the competitiveness of the auction, so bidding is one input among several. Raising the bid works and applies to every click you were already paying for, which is the arithmetic behind every pay per click account that got expensive without getting bigger. Improving relevance moves the same figure without that cost, which is the argument made at greater length under Quality Score.

A campaign losing heavily to both at once is usually too broad rather than underfunded.

Words you will hear

• Eligible impressions. Google’s estimate of the auctions you could have entered, based on targeting, approval status and quality.
• Ad Rank. The score that decides whether and where an advert shows.
• Absolute top. The first advert above the organic results.
• Auction. The moment a search happens and eligible adverts compete.
• Coverage. An informal word for the same idea, not a Google metric.
• Share of voice. The equivalent idea in traditional media, and not calculated the same way.

Why a high figure is not the target

The instinct on seeing a low percentage is to fix it. That instinct is usually wrong, and understanding why saves a great deal of money.

Impressions you did not get were the ones the auction ranked below the ones you did. They are the searches where your advert was less relevant, or where the competitor was more willing to pay because the search was worth more to them, quite possibly because their landing page converts a higher share of it. Buying your way to all of them means buying the worst of them at the highest price.

The exception is when the missing share is on your own name, or on the handful of searches that describe exactly what you sell. Losing those matters, because there is no better version of that search happening elsewhere. This is why the exact match column is worth more attention than the general one.

Reading it over time

A single figure tells you very little. The same figure across twelve weeks tells you what is happening to your market.

Falling impression share with your spend unchanged means somebody else arrived or somebody else increased what they were doing. Rising impression share alongside falling click volume usually means the searches themselves dried up, which is seasonal in most trades and worth knowing before it gets blamed on the account. Impression share that collapses on a specific date almost always matches a change somebody made, and the change log will name it.

None of these readings are available from the number on its own, which is the argument for putting the columns in your regular view and leaving them there.