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Surprise! AdWords Ad-Serving Myth-Busting

I feel kinda stupid. Either I didn’t read the AdWords Help on Ad Serving settings closely enough (again), or AdWords made something super non-intuitive (AGAIN). More likely, a little of both. I’m sure someone in the comments will tell me they already knew this LOL 🙂

When you create an AdWords campaign, you can edit the Ad Serving setting to rotate or optimize the ad distribution.


I thought that meant I could control whether the ads were given equal impressions. Not true, it turns out.

The insight given to me by one of our dedicated AdWords reps today is this:

Even when ad serving is set to Rotate, Ad Rank determines number of impressions.

Ad Rank can vary from ad to ad, because

  • Different ads cause different CTR with the same keywords,
  • Quality Score (QS) is largely determined by CTR, and
  • Ad Rank is the product of Bid * QS…

…so every ad has a different Ad Rank.

The Factors That Determine The Outcome of Auctions


I had already watched Chief Nerd Hal Varian’s video (Just kidding, Hal! You are the coolest nerd at Google, and nerds are awesome) on the ad auction twice. I guess I should have watched it thrice. Now I have:

Introduction to the Google Ad Auction

Still, he leaves out the ad auction -> impression relationship in this video.

The Rotate Ad Serving Setting: Myth and Truth

To clarify, here’s a chart of the misconception some of you may have shared with me, compared to the actual, real, true truth.


All of this happens when you notice that your AdWords ads are getting different Served percentages. Click that link to read more from AdWords help about it- you want to read part I.

Ad Serving Setting and Impression Share

  • If you have it set to optimize, the better Ad Rank show will show more often, and you’ll win more auctions and get more impressions.
  • Even your campaign is set to rotate ads, the overall lower Ad Rank can give you fewer impressions. Using the rotate setting can lower impression share.
  • An ad with a lower quality score would get fewer impressions because it would show off the first page more often. Even when average position is fairly high (1-4), that’s still an average; sometimes the ad could be showing on the second page or lower.

Hmm… Let’s Read This More Closely


Ha now I see it says “more evenly”. That makes more sense now. I feel truthier. I hope you feel more truthier, too!

Category SEO
Brian Carter The Carter Group

Brian is author of The Like Economy: How Businesses Make Money With Facebook and Facebook Marketing: Leveraging Facebook’s Features For ...

Surprise! AdWords Ad-Serving Myth-Busting

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