Circulation is a count of how many copies of a particular publication are distributed. Circulation audits are provided by the Audit Bureau of Circulations (ABC).
Readership is an estimate of how many readers a publication has. As most publications have more than one reader per copy, the NRS readership estimate is very different from the circulation count.
Readership estimates also show:
- The demographic profile of readers.
- What else they read and do.
The relationship between readership and circulation is known as readers-per-copy, i.e. readership divided by circulation. The number of readers-per-copy varies considerably by publication, as the following examples show