Shelf Balancing Study

I am planning a shelf balancing study (or maybe you could call it a shelf allocation study). I have paperwork on a study that was done six years ago, but so many things have changed since then that I think it's time for another one. Maybe it will help me plan this study to write it out, and maybe some of you have suggestions that will help, too.

The idea is to balance (allocate) the available shelving to the way each collection is used. Over time, some collections grow, some shrink, and some get moved to other areas of the building. The balance gets all out of whack and you end up with lots of extra space in certain areas, while others are way too tight. You also end up weeding books in popular collections just for space, while books in less popular collections have room to spare and are only weeded for condition or date.

(A great article on this idea is by Tony Greiner, called "Collection Development and Shelf Space: A Proposal for Nonfiction Collections." I'd love to meet this guy!)

Among the basics (circulation, collection size, number of shelves...all the things Mr. Greiner points out in his article) other things to consider include:

- How to break down the collections. I'm thinking of starting with non-fiction and going by Dewey range, so the breakdowns would be 000, 100, 200, etc. This may need to be broken down even further, though. 300s and 600s, for example, are HUGE collections, but only certain parts of each make up the majority of the range. In every public library where I've worked, personal finance books (332) take up much more space than books on etiquette (395) in the 300s. If you were balancing shelves in a youth non-fiction collection, it's probably the complete opposite. Health books take up more space in the 600s than something like the 660s (which includes things like chemical engineering and metallurgy. Public libraries usually have some books in the 660s, but generally not even close to as many as the 610s range on diseases and medical conditions).

- How much has each collection grown each year over the last five years? Consider this: a collection like art books in the 700s may continue to grow at a faster rate than weeding needs to be done. It needs more and more space since the collection grows steadily each year (that is, if its budget allows it to continue growing...another consideration!) Compare that to a collection like computer books that is more likely to stay closer to the same size over time. As you add new books, the older ones get weeded because currency is so important in that collection - more so than in the art books, anyway. You need to plan for less growth space for computer books (but do plan for some!!)

- How many items, on average, are on each shelf? Art books are big! Poetry books are small.

- How many books are generally checked out in each range at any given time? How many are generally on the shelf at any given time?

- Physical size needs to be considered. Art books are often very large and need more space. We don't want to put them on the high top shelves because they could hurt someone. Fewer shelves in that range, spread out more to accomodate large size, means that collection needs more space. A library that has a separate oversize collection can skip this consideration if they aren't included in the continuous range of collection you're balancing.

This is just the first round of brainstorming on this project. If you've done a shelf balancing/allocating study, or if you know of any more good articles or books on the topic, I'd love to hear about it!