Ad Group Impression Share

[#1]

Hey guys, in the learning center, it states the following about impression share at the campaign level.  

"Campaign: If you have more than one campaign competing in the same target market, we try to compensate for other campaigns within the same account.

For example, let's say Campaign A and Campaign B both belong in the same account. Out of the ten potential impressions, Campaign A shows twice, and Campaign B shows five times. A competitor takes the remaining three impressions. A campaign-level report will show an impression share of 40% for Campaign A (2/(2+3)) and 63% for Campaign B (5/(5+3)).
You can see that the impressions Campaign A lost to Campaign B is not factored in to the denominator when we calculate Campaign A's impression share. This example illustrates that it is a lost opportunity for your campaign only when the competitor wins the remaining potential impressions."

My question is whether or not this applies to the ad group level as well.

[#2]

 Hello Ryan;

Since lost impression share at ad-group level is relatively new; could you give us a direct link for this excerpt?

[#3]

If I am understanding your question, I think this is an issue of comparing/compiling the data across multiple levels of the account (?)....

If you are in the campaigns tab, the total numbers on the bottom line are for the agregate of all campaigns, which were active during the date range being viewed. If you are viewing the impression share columns, those numbers are for each individual campaign. Here is a terrible example:

Account level - All campaigns

                    Imp.     Imp. share

Campaign A   2             20%

Campaign B   5             50%

Total              7             35%

So, at the adgroup level:

Campaign Impression share = 75%

Adgroup 1 Imp. Share = 50%

Adgroup 1 Imp. Share = 100%

It's not always about the competitor getting the impression. The impression share could be lost due to rank, or budget. You are not losing impression share because of another one of your campaigns. You can only show one ad, per account, per possible impression instance. Impression share is essentially how many times your ad was shown, when it could have been.

Impression share             Lost due to rank               Lost due to budget

50%                                       25%                              25%

Do you have the impression share columns enabled?

Impression share

http://support.google.com/adwords/bin/answer.py?hl=en&answer=52760

Use columns to find specific performance data

http://support.google.com/adwords/bin/answer.py?hl=en&answer=2454071

[#4]

Hi Guys,

There seems to be some minor confusion. A campaign in your account may, in fact, sort of steal impressions from another campaign of yours. A typical case of this kind is when an awkward broad match keyword is the thief, often unintentionally on the advertiser's part. In such cases the calculations the Asker cited above are applicable and correct. 

Multiple ad groups within the same campaign constitute a parallel scenario. Hence the same is applicable to cases when impressions are lost by one ad group to another ad group in the same campaign. If it was not true it would not be true at the campaign level either, since adding up ad group level data should result in the campaign level data.

Best,

Lakatos