How does measurement of message exposure differ from measurement of audience comprehension of the message?

What are impressions?

An impression is a calculated but estimated way of telling us the potential audience reached by a certain medium, for example:

• newspaper
• television
• radio

 Although this estimation tells us about how many people were in a position to be exposed to the message, it doesn’t tell us how many people actually got the message, or for that matter, even retained it.

That’s where audience comprehension comes in. The easiest way to measure comprehension and retention is to survey the intended audience about what the message was and what they remember.