The difference and divergence between readership and circulation

What’s the difference between readership and circulation?

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 PAMCo 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.

Divergence Between Readership and Circulation

The relationship between readership and circulation is a complex one. Usually long-term trend data show a strong relationship between the two, but there can be changes, both sudden and gradual

In some cases, sudden period-on-period changes are a result of sample variation, particularly for smaller titles. However, around half of the period-on-period changes in readers-per-copy are statistically significant and it is important that PAMCo reflects these real changes in reader-per-copy.