Impression share data is nothing new in AdWords. It has been available for some time now but only at the campaign level. Google have recently announced that it will soon be available at the ad group level as well. This is a much welcome improvement because it will help identify problematic ad groups. Impression share at the campaign level was nice, however if your campaign had many ad groups, it was more difficult to determine which ad group(s) were causing the problems?

What is impression share? Google’s definition is as follows:

"Impression share is the percentage of impressions you received divided by the estimated number of impressions you were eligible to receive. Eligibility is based on your current ads’ targeting settings, approval statuses, bids, and Quality Scores."

That doesn’t seem to make much sense so Google have provided a nice analogy to help explain:

"An easy way to understand the value of impression share is to think of the online advertising landscape as a delicious pie. You and your competitors are each trying to nab the biggest slice of that pie. By tracking your impression share metrics, you’re keeping tabs on the size of your slice compared to the rest of the pie, which is being divided up and eaten by your competition!"

Impression share data is broken down into the following columns:

Impression Share: Explained above. Basically, how much of the market are you actually reaching.

Lost Impression Share (budget): If your budget happens to be too low, you will see a value under this column. This is Google’s way of telling you to increase your budget.

Lost Impression Share (rank): If your ad rank is too low, you will see a value under this column. This is Google’s way of telling you to increase your bids or improve the quality of your ads.

Exact Match Impression Share: What percentage of the impressions you could have received if all your keywords were exact match. You won’t see data for this column on the display network.

How can you see this data? At the campaign level and soon at the ad group level, click on the columns drop-down and choose customise columns. Then select "Competitive metrics" to see the available impression share columns.

As you begin to see the data, you will notice that the sum of the values within Lost IS (budget) + Lost IS (rank) = Impression Share.

More information on Impression Share can be found here.