The number of Impressions is a fundamental metric used in advertising. It means one exposure of an ad or commercial to an individual or household. A “gross” version of this number is the total number of exposures during a campaign. This number includes duplications, or multiple exposures to the same individual or household. How You Do It
Media planners calculate the number by referring to rate cards from specific outlets or to directories such as SRDS or Cision or Alexa.
After the fact, it is a measurement for reporting and analysis. It is a permanent record of where your advertising messages went.
This is a fundamental navigational metric for media planning and record-keeping.
By itself, it provides no analysis – for example, it provides no evaluation of an outlet’s credibility with the audience. It is important not to make this metric do more than it is meant to do.