Part 2- Be Prepared
If I’ve convinced you in my last post to consider transitioning your prep school collection from Dewey to the Library of Congress Classification (LCC), you are likely asking the next obvious question: How on earth do I actually execute this without losing my mind or shutting down the library? This post pulls back the curtain on the gritty digital, material, and personal preparations required to move thousands of books from a decimal system to an academic one. For context, this year we tackled 15,000 volumes in our general non-fiction collection. We also converted our reference collection, which began with around 650 volumes and an Alum section of around 300 volumes. We have a unique collection of around 2,000 volumes in a China Studies Collection that we set aside for next academic year. As I refer to the collection in this post, I am specifically referring to the 16,000 items in this year’s project.
Prepping the Machines
The first major hurdle is making sure your library catalog/software can support a living hybrid collection. For us, this meant ensuring users could find resources even if our collection was split between two entirely different call number systems during the transition.
Admittedly, this took several years of circling back and working closely with technical support before we cracked the code. While I am happy to share detailed Accessit procedures with anyone who reaches out, here is our general data workflow:
We ran a global update across our records to pull the Library of Congress call numbers from the MARC 050 field into an additional field. This automatically populated 77% of our general non-fiction collection with LCC data, giving us a baseline to work from (though we still had to find or build custom call numbers for around 4,000 resources).
In Accessit, custom additional fields cannot be easily exported into Excel. To get around this, we ran a retroactive tidy-up to copy the new LCC data from that additional field directly into the Abstract field.
This allowed us to run a report that could export everything into a highly flexible Excel master sheet containing:
Barcode
Title & Author
Publication Date
Current Dewey Call Number
New LCC Call Number (Abstract field)
Working in Excel and Sheets allowed us to see exactly which books needed manual cataloging and let us predict how much physical shelf space each LCC letter class (A–Z) would ultimately require. It also gave us flexibility to sort and filter sections and add additional columns for weeding, status updates, and conditional formatting to keep things organized.
Beyond the catalog, we also upgraded our printing process. Historically, we processed our small batches of new arrivals by typing spine labels manually. For a whole-library overhaul, this was unrealistic. Fortunately,our Dymo printer software allows direct data-piping from CSV files, automating the import process entirely.
Prepping the People
Before touching a single book, we needed to make sure we were versed in the nuances of LCC cataloging. This was imperative not just for the cataloging involved in reclassifying, but also as we transition to teaching students this new system. As our students came back to school in September, both my library assistant and I started class, too. We took a deep-dive Library of Congress Classification class through the online professional development portal Library Juice Academy. This gave us a solid understanding of the history and structure of LCC and the technical confidence to build correct Cutters and manage tricky classification decisions.
Your daily library tasks do not pause just because you are reclassifying. We were incredibly fortunate to get some bonus manpower this year. Even with that extra manual labor power, this project has consumed enormous amounts of time this academic year, and will bleed into the next. Because of our impending building move, we faced a firm timeline. Without that constraint, I might have taken a year to do our weeding (it would waste time and material resources to reclassify and re-label books that no longer belong on our shelves) and backend reclassifying before moving into the physical process of affixing new spine labels and reordering the shelves. Without that flexibility, we had a rolling process, Dewey class by Dewey class. (Check back soon for a Workflow and Process post that goes into greater detail!)
If you aren’t comfortable or confident with spreadsheets, that would be another area to brush up on. I lived in Excel and Sheets this year, and while I’ll share some pro-tips in the next post, comfort working within them is key in this scale of project. We used Excel for the largest sets of data, and some particular needs, but for data I needed to have more than one staff member using Sheets worked best.
Depending on your library’s budget, it may help to ask for a supply line bump for this kind of project. While we came in on budget, our operational supplies took up a much larger portion of our annual budget this year than usual.
Finally, do not underestimate the need for a fleet of book carts. They serve not just as transportation, but as roving, portable workstations. (See my rolling spine-relabeling station below!)
Prepping the Space
Using the proportions calculated from our initial Excel data pull, we mapped out how much shelf space each LCC class would need.
Initially, we planned to move books to their final alphabetical LCC locations immediately as we relabeled them, but we quickly realized this would cause massive, chaotic disruptions to the shelves mid-year.

Prepping the Materials
On the physical side, you need to prepare for the realities of your specific collection. We stocked up on standard supplies—spine labels, label covers, and barcode protectors—but we also discovered hidden project creep.
For example, our library had a legacy from the early 1990s: a unique black tape holding on book jacket covers. That tape is now deteriorating and flaking off. Every single book with this tape had to be stripped, cleaned, and fitted with a new cover before receiving its LCC label. We went through a small army of precision knives and fresh blades to clear away decades of old spine tape.
Instead, we chose a less disruptive path: we relabeled the books but put them right back where they were sitting in Dewey order. Yes, this meant the library was temporarily out of alphabetical order, but it kept our shelf space functional and stable. Because we have the unique advantage of moving the entire collection to a brand-new Upper School library building this summer, we can sort them into true LCC order during the move. Even if we weren’t moving buildings, I would still recommend this “batch-and-hold” method over constant, daily shelf-shifting.
We strategized our rollout to protect our students’ heavy research seasons:
The Trial Run (000s): We started relabeling with Class A. It was our smallest projected section and mapped perfectly from our existing Dewey 000s, meaning zero physical shifting was required to test our workflow. This was also a chance to work out the little kinks in the manual work of relabeling.
Expansion (100s and 200s): Next, we tackled the B Class, which cleanly absorbed our Dewey 100s and 200s onto the same physical footprint.
Planning around Research Projects (900s): Our history students write major research papers in the winter and spring. To avoid disrupting them, we jumped straight to the 900s before their research cycle started. We tackled Classes E and F (History of the Americas) right after the US History paper deadlines since those books wouldn’t be in demand anymore, followed by Class D (World History), in an attempt to have that section completed before the late spring regional history papers.
Filling Gaps (300): Next we jumped to the 300s, as many of the items pulled out of the 900s were H’s–what many of the 300s would reclass to–filling our temp shelving. Relatedly, there were many large gaps in the E’s–particularly E180s–that would get filled with books from the 300s. This helped us clear our flexible shelving for the next push.
The Wiggle Room: To make this work, we cleared out a specific section of shelving to act as a “temporary overflow working space.” When books didn’t neatly fit the section we were currently processing, they went to the overflow shelves to give us the spatial wiggle room we needed to keep moving.
Next Up…
In a future post, once the dust (so much dust!) has settled a bit, I’ll share the nitty gritty of our process and workflow.
Until then, order those spine labels, audit your data fields, and embrace the shuffle!