Theoretically, an impression is generated each time an advertisement is viewed and the number of impressions achieved is a function of an ad’s reach (the number of people seeing it) multiplied by its frequency (number of times they see it).
Note that impressions do not account for the quality of the viewings, or even whether the consumer actually “sees” the ad: an opportunity to view the ad, a glimpse or a detailed viewing all count as one impression.
The purpose of the “impression” metric is to understand how many times an advertisement is viewed.
The process of estimating reach and frequency begins with data that sum all of the impressions from different advertisements to arrive at total “gross” impressions.
Impressions (#) = Reach (#) x Average frequency (#)
Methodologies for estimating opportunities-to-see vary by type of media.
- ^ Farris, Paul W.; Neil T. Bendle; Phillip E. Pfeifer; and David J. Reibstein (2010). Marketing Metrics: The Definitive Guide to Measuring Marketing Performance (Second Edition). Upper Saddle River, New Jersey: Pearson Education, Inc.