The Mystery of the Light-Fingered Science Fiction Fans
I found 30 of the missing books on the shelf where they were supposed to be, which was a relief because it means that I don't have to worry about reordering any of them, but also a cause for concern because there aren't that many books in the SF/F collection, and somehow the people pulling holds aren't finding them on the shelf. That left 101 books still missing. My process is to put the item barcodes into Millennium and see whether another branch has the item, whether we have it in hardcover, etc, before I remove it from the system. After a while, I started to notice something interesting: many of the books were part of huge SF series.
I deleted 80 books, and almost half of them were Star Trek or Star Wars-related. Quickly searching the catalog, I found that we own 73 Star Trek paperbacks and 33 Star Wars paperbacks, which is about 10% of the collection. However, these series paperbacks accounted for 40% of those that I deleted, and several of those items had circulated several times before disappearing. All told, 30% of Star Trek paperbacks were missing and 36% of Star Wars paperbacks were missing.
Now, I do order the occasional Star Trek or Star Wars paperback when I do my monthly order. However, I should clearly make it more of a priority, since both the history of the collection (that slow accumulation of titles that led us to have so damn many of these books) and the pattern of theft (I always figure that missing books = some indication of demand) indicate that there's a higher interest than I had assumed. Sometimes patron demands can be measured outside of request forms and high circulations; thanks to my missing report, I am paying attention to something I had largely ignored.
The titles of some of my favorite missing SF series items:
Spock Must Die!
Wagon Train to the Stars
The Best and the Brightest
Kirk: The Star for Every Wandering