So it is the number of impressions you have received get divisible by the counted number of impressions that were available. Impression eligibility is based on a various factors like: Quality Scores, Ad Rank, bids, settings, and approval status.

This Impression Share metric type is a type of impression share in which it is found the estimated number of impressions you were eligible to receive and it is divided by the number of impressions received on the Search Network by the user.

On the Search Network for terms that matched your keywords exactly with one another.

Display Impression Share metric type is a type of impression share in which the counted number of impressions you were eligible to receive by the user is obtained by dividing the quantity of impressions received on the display Network.

When looking at a campaign’s health and overall performance then Impression Share is a vital metric that sometimes flies under the radar

There are a few of the main reasons this metric is so important are:

Impression Share is a good reflactor of the strength of your keyword set: You can feel confident that your coverage is so strong,If you have a very high Impression Share for both Exact Match and Standard.

 To improve campaign performance, It helps in guide you to expand your keyword set through Search Query Reporting or encourage you to add more negative terms.

Due to budget constraints it Helps to identify areas of missed opportunity : If you missing out on Impression Share due to Budget and you have a strong performing campaign or ad group that is then you can simply increase budget here to gain extra conversion volume and overall campaign performance.

Suggestions to Improve It-

• Adjust geo-targeting settings – When you may see a spike in impression share means that you decrease or restrict your location settings,. Setting a specific location or area for Targeting one only will allow you to focus all efforts on that one area, and allow you more control over a specific target..

• Improve your ad quality – On impression share,ad quality can also have an impact. If you can take steps to correct your PPC ads, then by virtue of quality score google will display those ads more frequently. By making it as specific and relevant try to improving your ad text as possible to the keywords in their respective ad groups.