Libraries and Statistics

I recently did a (very lightweight) analysis of our oversize book usage statistics at LHS and thought that some of what I did might be generally useful. Doing serious statistical analysis of collections at the branch level is difficult at this time due to the closed nature of Symphony data (the "Reports" tab remains empty and enticing to those branch staff with an interest in analyzing collection stats at the macro level), but here's what I did:

• Pulled 21 titles "randomly" from the oversized collection and recorded their Date Created (I don’t believe this is necessarily the date put on shelf, but it’s what we’ve got to work with) from Symphony, along with # of circs. This is approximately 1/6th of the on-shelf collection of oversizeds. I entered this information into an Excel spreadsheet so I could automatically...
• Divide circs by number of years held to get a rough circs/year number, using the formula (Warning, Excel pseudocode): =CIRCS/(TODAY()-DATECREATED/365)

This let me calculate things like average circulation/year for the sample (a 4.06, right on target for a district library), as well as see the individual circ/year for the titles (roughly 1/3rd below usage target, 1/3rd at usage target, and 1/3rd above).

Serious statistcians (or people in Collections) are probably laughing at my methodology here, but I thought this was neat. :)