Most of what I talk about at conferences is related to collection management and the use of statistics, benchmarks. I like that numbers really don't really lie. Collection metrics really can help us get rid of some of the emotional aspects of decision making, and focus on the true picture. Of course, everyone looks to circulation numbers as the first indicator of popularity or interest. Yes, I do think circulation numbers are interesting, but they are not the whole story and they certainly cannot be considered without a time factor or within a benchmark.
So just what is a "circulation" number?
Truth be told, circ numbers bother me. Maybe because many librarians put so much faith in them and use them a bit too liberally in describing library functions. Depending on your ILS, a circulation indicates that a particular item has been "checked out" by a patron. Does it count browsing or use within the library? (Think of a traditional reference collection). What about in cooperative situations where Library A loans the book to Library B's patron. How do those numbers figure into the picture? Taking this one step further, how does your ILS count a particular "circulation"? Does it count in-houses use differently? How about ILLs? How about renewals?
Having 10,000 circulations a week or month doesn't really tell us much. How many different patrons were served? How many utilize self checkout or need staff assistance? Do loan periods affect the circulation rates? How about when we compare to other libraries? Is a circ number at one library the same at another? Inquiring minds want to know!
On an individual item level, a circ number can indicate how times an item has been checked out. Again, this is only helpful with some context. How many times an item has been checked out is only helpful if you know when those checkouts occurred. If the item has 100 total checkouts, but hasn't been touched in five years, maybe its time for weeding.
Yes, circulation numbers are one indicator of a library's function, the danger is assuming that circulation numbers indicate a general level of performance. As electronic information now a big aspect of library services, where do these items fall in the statistical picture? Although the public might think we just "check out" books to people, library service is much more. What we need is a comprehensive discussion of library performance standards and some metrics to match!