← Glossary
What is impression share?
Impression share is the percentage of the auctions you were eligible for in which your ad actually appeared.
Formula
Impression share = Impressions ÷ Eligible impressions
The value is in the two 'lost' figures beneath it. Impression share lost to budget means you ran out of money; lost to rank means you weren't competitive enough. They call for opposite responses.
Lost to budget with good results is the clearest signal in advertising that you should spend more — the demand is proven and you simply stopped buying it.
Lost to rank means more budget won't help. The fix is relevance, bids, or accepting that some auctions aren't worth winning.