I had been wondering about this for a while. I was going back and forth in my mind about which way it was working. Thanks for clearing that up. Nice writeup.

I’m wondering because I’ve got two virtually identical ads running as A/B, with the same set of keywords (QS on those is almost all 10/10). The only difference is that I’m using DKI in one of the ads’ headline. For the non-DKI ad, I’ve got impression share of 95.45%; for the DKI ad I’ve got 4.55%. AND… the non-DKI ad has a 1.48% CTR, versus 3.03% CTR for the DKI ad. (I’m viewing stats for just the past 7 days here, and ad rotation is optimized.)

So, double the CTR for the DKI ad, but drastically less impression share… which is exactly the reverse of what should be happening, according to Google.

Only thing I can figure is that there’s some unseen ad quality score going on based maybe on the fact that the DKI ad has only been running for the past two weeks, versus a much longer period of time for the non-DKI ad. (Again, I’m narrowing down the scope of the stats to just the past 7 days, though.) Would the newness of the DKI ad version have an effect on the ad score, and thus somehow be skewing the ad impressions it gets?

(And re: “ad quality score”… I keep seeing references to this term, but it seems the only real quality score that you can see in AdWords is _keyword_ quality score. There is no viewable _ad_ quality score, except for ads getting impressions on the content network. And since I just today turned on content network for this campaign, there is no existing history for content network yet.)

Confusing enough, huh? FYI, I’m just coming in on this ad campaign (new job I just started a few weeks ago), so it’s a bit of a muddle, but this impression percentage thing is puzzling. As Brian said, “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.” Which isn’t happening — it’s exactly the opposite. And, “An ad with a lower quality score would get fewer impressions because it would show off the first page more often.” Which makes me wonder how DKI would impact this… although average position for these ads is 2.8.

Any ideas much appreciated…

Steve S.

I could not disagree with the logic of this post, and it’s useful to know (and not unsurprising), but with rotation ad impressions are pretty closely shared with no large bias one way.

To improve your clickthrough rate, and therefore quality score, you should set your ad headline text to include the keyword you are bidding on.

How does Impression Share reflect on my campaign’s performance?
Nada.

How is my daily budget distributed?
Nope but Oh there it is a helpful article:
Which ad delivery option is best for my campaign?
Oh not that helpful…that’s sad.

Better check again ClickEquation Craig Danuloff’s amazing articles about impression share .

Thanks a lot Brian!
Most important PPC article this year so far!

Either way, it’s a good reminder that not everything is as it appears in AdWords and you often have to look deeper for the answer.