Collection Development Trends Across the Nation

If only libraries had infinite stacks! Unfortunately, the shelf space in libraries is limited. For many libraries with full shelves, when a new title comes in, an older one must go out.

Determining which titles stay and which ones need to go isn’t as easy as it may sound. Librarians deploy a mix of data and expertise about the community they serve to create collections that engage their patrons.

But sometimes the right decision is not crystal clear. If you’re a librarian, you may have asked yourself things like:

How much of the library should be devoted mysteries? Which mysteries should be in the collection? How do I know that we're making good use of our budget?

To shed some light on these important questions, we reviewed print holdings and circulation trends across hundreds of library branches nationwide to understand:

  • What genres earn the most shelf space in the average library?
  • How do library collections compare to the inventory of bookstores who are serving the same community?
  • What is the “batting average” for selecting books that will circulate well, thereby maximizing a library’s collection budget?


Subjects That Receive the Most Shelf Space

In most cases, the most shelf space is allocated to genres that circulate well. On average, Mysteries and Thrillers take up the most shelf space in US library branches (7.6% of print titles). Juvenile Fiction books about animals are the second largest category with Romance and Biography following closely behind.

However, Mysteries and Thrillers don’t actually receive the highest circulation by genre (5.8% of libraries’ total circulation). Instead, the highest circulating genre is actually Juvenile Fiction books about animals. (No librarian is surprised by this!)

When a library compares the percentage of their collection devoted to a certain genre to the corresponding circulation of that genre, they can learn some important things about their collection. A large gap between the two measures could point to several causes. It may be a sign that the collection should be balanced to reallocate budget to higher circulating areas. It could also be due to the physical layout of the library or another factor related to their unique patron community. This exercise raises some good questions and ensures that the library is properly allocating not only shelf space but also purchasing dollars!


Inclusion of Current Top Sellers 

Both libraries and local bookstores serve the same population of readers. Libraries can leverage knowledge of what is happening down the street at the bookstore to enhance their collection and vice versa. In general, the vast majority of books selling well at the local, independent bookstore can be found in a community’s library… but not all of them. That’s where things get interesting.

The average library collection for Mysteries and Thrillers lacks 10 titles that are selling at over half of independent bookstores across the country. About the same number of high-performing titles are also absent from libraries’ Juvenile Fiction about animals and Biographies collections (12 titles).

On the flipside, the number of Romance titles selling well at bookstores that are not available at the average library? Just ONE.

This raises some interesting questions. Many “missing” titles may actually be intentionally left out of a library’s collection. There are a number of decisions factors that librarians take into account when deciding how to spend their collection budget. However, looking at a library’s collection this way serves as a nice “double-check” and may lead to better decisions in the future.

Let’s look at an example of how a library might use this information at a very granular level. One of those “missing” titles at a library in the northeast with over 7,000 Mysteries and Thrillers in their collection was Megan Miranda’s The Perfect Stranger published last April. When discovered, the team determined that it was, in fact, inadvertently overlooked so they added the title to their next order!


Hit Rate for New Titles

Collection development is an art, but everyone wants to know that their purchasing decisions are making good use of their budget. While data is tremendously valuable in aiding in the selection process, it’s impossible to know with 100% clarity whether a new book will circulate well… but it is possible to improve the library’s “hit rate!” This is the percentage of newly selected books that have circulated. Tracking this measure can inform future purchasing strategies.

For example, across all of our US libraries, 94% of new Biography titles on the shelves for at least three months have circulated.  Similarly, on average, 96% of recent Historical Fiction titles have already circulated.  That’s an amazing hit rate!

But home runs don’t happen all the time. Lower “hit rates” for certain genres may be expected, but if a library’s percentage is significantly above or below the national average for that genre, it could point to the need to shake up the purchasing strategy to make better use of the library’s collection budget in the future.

Lessons can also be learned by looking at specific titles that were recently selected but haven’t circulated (i.e. didn’t “hit”). For example, in a southwestern library with over 10,000 Biography and Memoir titles, The Quarterback Whisperer was expected to be popular with their patrons yet hasn’t circulated since it arrived twelve months ago. Insight can be gleaned from reviewing selection choices regularly to see if there are any trends that may inform to title selections.


How does your library compare?

Every library, along with the community it serves, is unique.  Many have certain collections that are especially relevant to their patrons – such as mining history in the Mountain West or farming guides in certain rural communities.  Yet for the majority of a libraries’ holdings, lessons can be learned by looking at best practices based on the aggregation of expertise from libraries across the nation.

Considering how your library compares to national averages and whether that difference is meaningful is not only interesting – it’s actionable. This data drives goal setting while informing both selection and weeding strategies. For example, does your library devote more or less of your collection to Literary Fiction than the average 2.0%?  Or the 2.8% to Board Books?  Like the average library, do you aim to have at least 79% of the Young Adult Science Fiction and Fantasy titles that are selling well at independent bookstores?

Compare your library’s collection to the national average below. How does it differ, and why might that be?

Collection development is a complex but vital function for our communities’ libraries. Doing it well will always depend on the skills and expertise of librarians, but data can help. Also, for data nerds and book lovers like us, it’s also just a lot of fun!