Exact Match IS Report -how to use this report?

Impression share report is one of the best report introduced by Google

[Prasoon2096]

Impression share report is one of the best report introduced by Google, Which gives right directions to your Optimization. With impression share Report, there is a Exact match Impression share report, after going through few articles about this report they left me puzzled, don’t have any idea how to use it efficiently
The interpretation which impressed me most was this report gives you “percentage of the impressions that were triggered by users typing in your keywords exactly. Let’s say you have the keyword “used cars” on broad match.. if one user’s query string was “used cars” and another was “buy used cars in New York,” your ad could have been triggered both times. However, you would only get a 50% Exact Match IS on those two impressions”
This suggests me if your exact match IS less than 40% then you have to work on your keyword list.
If anyone has different idea about using it can share their experience.

Thanks.

[Yoshimi]

Impression share is how many times your ad is being shown out of the number of times it is possible for it to be shown.

Say your keyword is blue widgets, and there are 100 searches a day which trigger ads for blue widgets, there is [potential for your ad to be shown on every single occasion, 100 times. But if the impression share report shows that your ad is only being shown on 50 of those 100 potential searches, it indicates a problem.

This is not a keyword list issue, generally it suggests that you don't have enough budget to be seen for all of those searches, or your rank isn't high enough for you to be seen for all of those searches. If you want to improve your impression share, you need to either, increase your daily budget, increase your QS or increase your bid price.

[Prasoon2096]

Thanks Yoshimi, i completely agree with you, impression share showing me that how many impression i'm losing against total number of impression available in market... in column Lost impression (budget) & lost Impression (Rank) it gives you info about Lost impression and the corrective steps are suggested by you .. but there is one more column of Exact Match IS & my entire post was to know how we can use this report effectively?

Thanks.

[Yoshimi]

your general IS is how many searches could potentially trigger your ads, the Exact match IS is how many people searched for your exact match term, so if yoour keyword is [blue widgets] how many people searched for blue widgets, and what percentage of those searches did you appear for.

I don't see how a low IS can relate to keyword expansion?