From: Frederick Friend <[log in to unmask]> Date: Thu, 19 Apr 2012 12:57:08 +0100 Ann has raised a very interesting topic which goes to the heart of how we measure the value of libraries. It could be said that a library's value does not lie in the number of uses of items in its collection, but unfortunately descriptions of value without numbers attached to the descriptions do not cut much ice with those providing the money to support libraries. And yet arriving at reliable and comparable usage statistics is an impossible task, for the reason Bryan Skib outlines, i.e. that so many variable factors enter the calculation. Any number has to be accompanied by an explanation of the factors used to calculate the number. Change one factor - such as the percentage of older material - and the number becomes meaningless in talking to policy-makers. What can be valuable are year-on-year comparisons starting from a reliable baseline, and used in a context which takes account of the profile of a particular library. So for example, it would be possible to compare the usage of digital items in a particular library over time, building in a growth factor for the size of the collection. However, it would be very unreliable to compare that statistic with a figure for the usage of paper items over the same period, given the fundamentally different factors which differentiate electronic usage from paper usage. A focused statistic could help a library in making a case for support of the library for particular resources, but the more general the statistic and the greater the attempt to make comparisons between libraries, the more open to challenge any statistic will be. Good luck to all library statisticians! Fred Friend Honorary Director Scholarly Communication UCL -----Original Message----- From: "Skib, Bryan" <[log in to unmask]> Date: Wed, 18 Apr 2012 16:30:40 +0000 What counts as use? For reading, there would have to be leveling off unless campus enrollments and staffing increase. How much can one person consume in this manner? Expansion of access to alumni or the general public would of course change the demographics. Further, the max number of uses will be distributed across an ever larger body of materials, competing for attention. The percent of older material that continues to see use should be higher for digital than for print, given ease of access. Will aggregate collection management and demand-driven acquisition strategies reduce the portion of our collections that never see use? Will restrictions on resource sharing reduce the external use of what we choose to license? If the question is about use of online reference works and A&I services, users may well prefer other tools. Higher portions of the content might see a different form of use to the degree that large-scale full-text searching or textmining is enabled. My local picture strikes me as mixed, with continued (but slowing) growth in use -- and yet I hesitate to jump to conclusions since (overall) we are not always comparing apples to apples, or counting the same things in the same way. Bryan Skib Associate University Librarian for Collections 818 Hatcher Library University of Michigan