What is Search top IS in Google Ads?

Google groups Search top IS with its prominence metrics, which give you a sense for your ads' placement on the page. Unlike average position, Google says, these metrics don't reflect the order of your ads compared to other ads, but the actual placement of your ads on the search results pages.

The column beside it is easy to mistake for it. Search top impression rate, labelled Impr. (Top) %, is the percentage of your ad impressions that are shown among top ads. Our reading: the rate describes where the impressions you won appeared, and the share describes how much of the top of page opportunity you won.

Google does not recommend using the rate columns as a target to set your bids, because sometimes they may decrease as bids increase: higher bids may allow you to enter more competitive auctions in a worse location. It names Search top IS among the metrics you can use as a target if you want to increase the percentage of your ads that show anywhere among top ads.

Google calculates Search absolute top impression share over the same estimated number of impressions you were eligible to receive among top ads, counting only impressions as the very first ad among top ads. Our arithmetic from those two definitions: for the same rows and dates, absolute top impression share cannot exceed top impression share. Two further columns, Search lost top IS (rank) and Search lost top IS (budget), report how often your ad didn't show anywhere among top ads due to poor Ad Rank and due to a low budget.

Search partners don't distinguish between 'top' and 'others', Google notes, and won't be included in location segmentation or impression share data. Riibon's own metric layer marks top impression share as a ratio that is never summed or averaged across rows.