Data on circulation of books

["Joseph J. Esposito" <espositoj@gmail.com>]

Perhaps the members of this mailgroup can help me with some 
questions about the circulation of books in academic libraries.

A distinguished academic librarian told me that "most books never 
circulate."  Allowing for rhetorical exuberance, I was wondering 
what the facts are behind "most" and "never."  Is it that "many 
books circulate only rarely," or "some books never circulate, but 
a larger group circulates only rarely," or "almost all books 
circulate, but a sizable portion circulates rarely,"--or some 
other qualified formulation?

The questions that come to mind are these, defining "books" in 
the ordinary sense (e.g., no other media types and hardcopy only; 
and not including books that are not designed to circulate such 
as reference books):

*What percentage of books never circulate at all?  Does this 
percentage vary by the size of a library?

*What percentage circulate rarely (assuming that there is a 
library convention for what "rarely" means in this context)? 
This would be the so-called Long Tail of a collection.

*Are even those books that never or rarely circulate findable in 
an electronic card catalogue, which is searchable by various 
means, or is the lack of circulation a function of inadequate 
"finding" tools?

*If the full text instead of just metadata of rarely circulating 
books were exposed to search engines of various sorts, what is 
the expectation for the increase in circulation?  In this context 
presumably online viewing would count as a form of circulation.

What's driving these questions is what the practical effect of 
mass digitization will have on materials use.  My hypothesis is 
that for books there will be a discernible but modest increase in 
use.  Any information that could help me prove or disprove this 
hypothesis would be welcome.

Joe Esposito