- Definition
- Impression share is the impressions an advertiser received divided by the estimated impressions it was eligible to receive.
Google splits the lost share into budget and rank, and reports variants such as top and absolute top impression share. Only the advertiser can see these figures for its own campaigns.
An independent monitoring tool cannot calculate another advertiser's impression share. It can only report how often a domain appeared in the searches it checked.
How Ads Lighthouse observes it
Ads Lighthouse reports observed visibility, a share of monitored searches, and labels it as a sample measure. It never presents it as impression share.
Official sources
Sources checked on .