"Our impression share is 40%" gets said in a lot of review meetings as if it were a diagnosis. It isn't. On its own, impression share tells you that you missed 60% of the auctions you were eligible for. It does not tell you why, and the why decides what you should do next.
Split the loss before you touch anything
Google splits the missing share into two columns, and they point at completely different problems:
- Search lost IS (budget). The share of time your ads did not show because the budget ran out. Google reports this at the campaign level only.
- Search lost IS (rank). The share of time your ads did not show because your Ad Rank was too low to enter or win the auction.
On a recent audit call, the first thing we pulled was these two columns. The campaign was losing 42% of its eligible impressions to budget, which reframed the whole conversation. The team had been rewriting ads to fix "low visibility" when the campaign was simply running out of money before the day did.
Lost to budget: more money is an option, not the answer
Budget loss tells you more auctions were available. It does not tell you they would convert at the cost you are paying now. Before raising the budget, check that the campaign is profitable at the margin, meaning its CPA and pipeline hold up, not just its average. The next slice of auctions is usually more expensive than the last.
If it passes that test, raise the budget in steps. We use 20 to 30 percent at a time, never 2x, and read the result at the new spend level.
Lost to rank: fix relevance before you raise bids
Rank loss is where most accounts overpay. The reflex is to raise bids, but Ad Rank also depends on ad quality: expected click-through rate, ad relevance and landing page experience, the same inputs behind Quality Score. Those are cheaper to improve than bids.
Our first move is the search terms report. Look for the high-volume queries your ads are already matching that none of your headlines address. If people are searching a phrase a thousand times a month and your ad does not say it, write an ad that does. That improves relevance on exactly the auctions you are losing.
One caution on Smart Bidding. When a target CPA or target ROAS strategy sits out auctions it predicts will convert above your target, some of that can show up as rank loss. That is our read from running accounts rather than something Google spells out. A bit of rank loss on a target-based campaign can be the strategy doing what you asked, so check the target before you blame the ads.
Two ways the number misleads
It can rise without any growth. Impression share is impressions divided by Google's estimate of the impressions you were eligible for. Google notes that cutting your regional targets can raise impression share while shrinking the pool of impressions available to you. A higher share of a smaller pie is not progress, so never set impression share as a standalone KPI.
It is an estimate. Google estimates eligibility from auction data, so small swings do not mean anything needs fixing. The columns update within one to two days. And if the budget ran out at any point in your date range, Google hides lost IS (rank) on the Ad groups tab, so read it at the campaign level.
The takeaways
- Never read impression share alone. Add Search lost IS (budget) and Search lost IS (rank) next to it.
- Budget loss means more auctions were available. Raise spend only if the campaign is profitable at the margin, and in 20 to 30 percent steps.
- Rank loss usually means relevance. Match your headlines to the high-volume search terms you are already triggering before you raise bids.
- Narrowing targeting inflates the share. Judge growth on conversions and pipeline, not the percentage.
Common questions
What is the difference between Search lost IS (budget) and Search lost IS (rank)?
Search lost IS (budget) is the percentage of time your ads did not show because the budget ran out. Search lost IS (rank) is the percentage of time they did not show because your Ad Rank was too low. Google reports lost IS (budget) at the campaign level only. The first points at money and the second at bids, ad quality and relevance, so they call for different fixes.
Should I raise my budget if I am losing impression share to budget?
Only if the campaign is profitable at the margin. Lost IS (budget) tells you more auctions were available, not that they would convert at your current cost. Check that the campaign's cost per acquisition and pipeline hold up, then raise the budget in steps of 20 to 30 percent rather than doubling it.
How do I fix impression share lost to rank?
Work on the parts of Ad Rank you control before raising bids: ad relevance, expected click-through rate and landing page experience. A practical first step is to check the search terms report for high-volume queries that none of your headlines address, and write ads that match them.
Why did my impression share go up when nothing improved?
Impression share is a ratio of impressions to estimated eligible impressions. Google notes that narrowing your targeting, such as reducing your regional targets, can raise impression share while shrinking the pool of impressions available to you. A higher share of a smaller pool is not growth.
Why is my Search lost IS (rank) column blank at the ad group level?
Google does not show lost IS (rank) on the Ad groups tab if the campaign ran out of budget at any point during the selected date range. Check it at the campaign level, or pick a date range where the budget did not cap delivery.