Your outranking share can rise without you beating anyone

Your outranking share against a rival can climb in a month when, every time both ads showed, theirs sat above yours. That follows from Google's own definition, and the working is ours, not a sentence Google writes.

Google says outranking share tells you how often your ad ranked higher in the auction than another advertiser's ad, or if your ad showed when theirs didn't. Our arithmetic from that definition: if the rival's ad sat above yours in every auction where both showed, none of your outranking share came from ranking above them. All of it came from auctions where their ad was absent, so a month in which their ad showed less often can lift the number with no change in how your ads compare.

The auction insights report for Search campaigns provides six statistics, and three of them describe you against one named rival. Each counts a different set of auctions.

Overlap rate is how often another advertiser's ad received an impression when your ad also received an impression. Position above rate is how often the other advertiser's ad was shown in a higher position than yours was, when both of your ads were shown at the same time. Outranking share, as above, also takes in how often your ad showed when theirs did not.

Our reading: position above rate is the only one of the three confined to the auctions where both ads showed, so it is the column that measures the head-to-head. Outranking share mixes the head-to-head with the rival's absences, and overlap rate tells you how much of your traffic each of those two parts can draw on.

This is our method, not Google's. When outranking share against a rival goes up, look at the other two columns on the same row, for the same dates.

If overlap rate fell in the same window, more of your impressions came with no ad from that rival, and Google's definition of outranking share takes in how often your ad showed when theirs didn't. If position above rate held steady, the rise came from their absence, not from your ad sitting higher. If position above rate fell while overlap rate held, you are winning more of the auctions you both showed in, which is the version of the story worth reporting as progress.

Shopping is harder. Google lists three statistics for Shopping campaigns, impression share, overlap rate and outranking share, and position above rate is for Search campaigns only. Our reading: on Shopping you can see that a rival's ad showed less often alongside yours, but you cannot isolate how the two compare when both showed.

It does not say why a rival's ad showed less often. Our reading: a paused campaign, a smaller budget and narrower targeting would all look the same from your side of the report, and none of them is something you did.

Two more limits are Google's. The report doesn't show insights when impression share is less than 10%. And the impression share shown for a competitor in your report may differ from the impression share that competitor can view in their own report. Google adds that competing advertisers' eligible impressions may only overlap with a percentage of your eligible impressions.

Our reading: a rival who looks beaten in your table may be doing well in auctions you never see. For what a genuine rise in competitive pressure looks like in the same report, overlap rate and position above rate climbing together, see our page on CPC rises.