Lost impression share (rank) is the percentage of times your ad was eligible to appear but did not, because its Ad Rank was too low to win a place or to clear the minimum needed to show. In Google Ads it appears as “Search lost IS (rank)” for search campaigns and “Display lost IS (rank)” for display.
How lost impression share (rank) works
Every time a search matches one of your keywords, Google runs an auction and gives each eligible ad an Ad Rank. Ad Rank combines your bid, the quality of the ad and landing page (expected click-through rate, ad relevance and landing page experience), the expected effect of your assets, and the context of the search, such as device, location and time. An ad must also clear an Ad Rank threshold to show at all, and Google sets that threshold auction by auction, taking into account ad quality, position and the nature of the search.
When your ad loses because others ranked higher, or because it fell below the threshold, the impression counts as lost to rank. Rank loss is reported down to keyword level, so you can see where it happens.
Two related columns narrow it down further. “Search lost top IS (rank)” shows how often a low rank kept you out of the ads above the organic results, and “Search lost absolute top IS (rank)” how often it kept you out of the very first position.
Why it matters
A high lost IS (rank) means people were searching for what you offer and your ad was not there. Adding budget will not change that, because money was not the constraint. The fix lies in the auction itself: a better bid, a more relevant ad, a better landing page or stronger assets.
It is also an early sign of competitive pressure. If rank loss rises while nothing changed in your account, another advertiser has probably entered the auction or raised their bids, and auction insights will usually show who.
Common mistakes
- Responding only by raising bids. If the Quality Score components are weak, higher bids buy positions at inflated prices.
- Chasing 0% on every keyword. Winning the last few per cent of impressions on a generic term can cost far more per click than those clicks return.
- Ignoring the landing page. A slow page, or one that does not match the search, pulls down Ad Rank for every keyword pointing at it.
- Running ads without assets. Sitelinks, callouts and other assets count towards Ad Rank, so an ad without them competes at a disadvantage.
- Accepting high rank loss on a brand campaign. On your own name it usually points to a settings problem or a competitor bidding heavily on your brand.
How to act on it
Sort keywords by lost IS (rank) and conversions together. Start with terms that already convert well and lose a large share to rank, since that is where better rank is most likely to pay. For each one, check the Quality Score components and fix whichever is marked below average before touching the bid: tighten the ad copy to the search, improve the landing page and add relevant assets.
Only then raise bids or loosen targets, in small steps, watching cost per conversion as you go. Compare with lost impression share (budget) so you know whether money or rank is the main limit. This diagnosis sits at the centre of how I run Google search campaigns.