Two common message delivery metrics that measure how much of the target market is exposed to the advertisement and the number of times they are exposed are:

Effective reach and Frequency

Explanation:

Effective Reach is percentage of target audience that is exposed to a particular ad and receives given message to affect sales and purchase who are reached at or above effective frequency level. Here effective frequency level is the number of exposures necessary to make an impact and attain communication goal.

Effective reach is used in application of statistics to advertising and media analysis to calculate the effectiveness of ad and means used for ad. Effective reach is a time-dependent summary of aggregate audience behaviour.