A couple of weeks ago, we (the librarians in my department) were tasked with running reports that would show how many books we ordered in the previous fiscal year, the lag time till checkout, the number of times the title circulated, and the number of times the title was placed on reserve. Then, we were told to go figure usage statistices. We weren't given any specifics, just to go figure what we thought was reasonable and bring it to the librarian's meeting in two weeks.
I love Excel and am fascinated with statistics. So, another librarian and I sat down and did some quick stats. What we chose to look at were the the total items circulated, total circulations, average lag time for an item to circulate, percent of items ordered that circulated, and the number/percent of items that circulated in 30, 90, 120 and more than 120 days. We also looked at the number of video recordings that were ordered and that circulated (number and percentage). For music, we also looked at the number of sound recordings that were ordered and circulated. The numbers were looked at by department and for the last fiscal year.
The results were interesting. In all cases, the circulation numbers were higher than the the total of the items circulated. What this told us was that while a certain percentage circulates (average was about 30% of items ordered circulated), those items generally circulated more than once. In some departments, 50% of the items that circulated circulated more than once. And where videos were ordered, in most cases a high percentage of the videos circulated; 100% circulation in some cases and in one case 0% of the videos ordered circulated. Our highest three departments circulated 67% and 61% of the ordered items. Our lowest circulation for a department was 11%. Overall, 35.41% of what was ordered circulated; 25 out of 42 departments circulated more than 30% of items ordered, three departments circulated more than 50% of ordered items. The average lag time for an item to circulate is about five months. 58.07% of circulated items circulated in 120 days or less. 51.78% of videos ordered circulated - videos accounted for 1.39% of materials ordered, but 2.03% of materials circulated.
I am fascinated by these results and a little heartened. I had stepped up the number of vidoes and multi-media for some of the collections I develop. The numbers show me that the videos that have been ordered in the past are circulating, so ordering more is probably a good thing. What I'm not sure of is if these numbers are good. I did pull the ACRL Standards for Libraries in Higher Education (2004). At a glance they don't give any numbers for circulation, but rather suggest looking at "Ratio of circulation (excluding reserve) to combined student and faculty FTE," and "Ratio of volumes added per year to combined student and faculty FTE." Again, nothing is given as to what would consitute a good number here, but at least it's a guideline. Unfortunately, I don't have the faculty and student numbers for last year, but I'm thinking that it wouldn't be bad to see how those ratios look against what we've already done.