Sunday, July 29, 2007

PL 22/07: NTC – Visitors and users

Filed under: statistics — plinius @ 12:56 pm

butter2.jpgLibraries generally find it easier to count the number of loans than the number of visitors.

All loans are registered, by manual or electronic methods. Electronic systems can show the number of loans day by day, or even hour by hour. Manual loans can be added up at the end of each day. If there are libraries with manual systems that skip the daily counting, they can get a good annual estimate by using counting days, as explained earlier.

Visitor numbers are more tricky. Many libraries have electronic counters at the entrance. Visitors cross the beam twice – going in and going out, and libraries often calculate the number of visitors by dividing the total by two.

But I would not rely totally on electronic counters. We should distinguish between visitors that come to libraries as customers – and visitors that just happen to pass the beam – including dogs, messengers and children running in and out. The instrument – in this case the counter – should be calibrated. We can do this by selecting a sample of days (or hours) and carry out a manual count while the electronic counter is running.

Manual counts are best carried out on a sample of days throughout the year. Manual counts have the advantage that some personal characteristics – gender, and to some extent age – can be included as well. A simple way of separating children from the rest, is to see whetrher they are below or above a a particular height (like they do in some amusement parks).

By calculating the number of loans per visitor, we also get an idea of the library profile: is it mainly a place for lending or a place for reading and other activities on the premises.



Complete teaching materials for Numbers that count – as a single file (Google Docs). – 18 pp.



  1. […] 1530-1600. When books meet users: how to measure  lending – and the number of visitors […]

    Pingback by PL 19/07: NTC - Program « Pliny the Librarian — Sunday, July 29, 2007 @ 1:23 pm

  2. […] PL 22/07: NTC – Visitors and users […]

    Pingback by PL 23/07: NTC - What happens inside libraries? « Pliny the Librarian — Sunday, July 29, 2007 @ 1:54 pm

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