Collective collection has become part of the librarian argot. Coined by our colleague, Lorcan Dempsey, the term emerged from OCLC Research’s work analyzing library collections at scales above the institutional level—group, consortial, regional, national, and even global.
The best way of understanding collective collections is to start with WorldCat, which is a global registry of library holdings. Taken together, these holdings document the sum total of materials available in library collections worldwide—or at least a close approximation. In this sense, WorldCat represents the collective collection of the global library system as a whole.
WorldCat is also a good starting point because, in our work, collective collections large and small are all carved out of WorldCat data. A collective collection is formed by identifying all of the holdings for a group of institutions in WorldCat, aggregating them, and then eliminating duplicate holdings to yield the set of distinct publications held across all the local collections in the group. The size of the group can range from two institutions to thousands.
Bringing collective collections to life
Analysis of collective collections is important because it helps us understand aggregations of collections as more than just abstractions. By surfacing collective collections in WorldCat data, we see that they are in fact finite resources with clear boundaries, possessing properties that can be measured or otherwise described in ways that provide useful intelligence. This intelligence can inform decision-making around collections at both the local level and within multi-institutional cooperative settings.
Consider, for example, the notion of a North American print book resource—the collective print book holdings of all libraries in the United States and Canada. Managing down print monograph collections by moving them into some form of shared stewardship has been a matter of keen interest for academic libraries, as they seek to leverage new efficiencies while preserving the value-creating capacity of the legacy print investment. The overall size of the North American collective print book collection, as well as its geographic distribution and other features, are important data points in support of developing shared print management programs. But what does this collective collection actually look like? It turns out that it contains 45.7 million distinct print book publications (as of January 2011), and is distributed regionally like this:
In the picture, the North American collective print book collection is broken down into a network of regional-scale collective collections. We see instantly that the largest regional concentration of print books is in the northeastern United States, with smaller yet still substantial concentrations in the American Midwest and on the west coast. We see a constellation of much smaller regional collections scattered around North America, and note sizable American and Canadian “extra-regional” collective collections, accounting for print book holdings located outside the regional clusters. In short, we see the contours of a print book landscape emerging—a sense of how large the resource is, and where it is located. And this in turn provides a foundation for building effective cooperative strategies around monographic print management.
Add a collective collection to your toolbox
Karla Streib of The Ohio State University has generously noted our collective collections work, remarking: “Perhaps the most influential descriptive studies have come from OCLC Research, which has shared reports outlining levels of uniqueness, as well as duplication, among various aggregations of library collections. This growing body of computationally intensive analysis of the collective collection has also begun to clarify geographic distribution and other key characteristics of library collections relevant for making decisions about coordinating activities. There is a new understanding of collections at scale. (italics added)” Clarification … relevance for decision-making … promoting new understanding: this is precisely what we hope to achieve with our analyses of collective collections.
Collective collections will continue to be an important concept for libraries, surfacing in at least three important contexts:
- Strategic planning and decision support: Understanding the nature of the collective collection around which cooperative arrangements are built is an essential element for developing and managing shared collections.
- Systems and tools: Collective collections are being incorporated into, or are implicit in, a variety of collection management resources, such as group catalogs and collection analytics tools.
- Research: Collective collections are a valuable analytical construct for advancing thinking about collection management. They are also useful for other kinds of research, such as culturomics studies looking at cultural trends in segments of the published record.
WorldCat, with its nearly 400 million bibliographic records and 2.4 billion holdings, is well-suited for working with collective collections in all three of these areas.
A collection of collective collections
We have just released a new study, Strength in Numbers: The Research Libraries UK (RLUK) Collective Collection, which describes the collective collection of a consortium of leading research libraries in the UK and Ireland. We will soon begin a new analysis of the collective collection of the Universiteitsbibliotheken & Koninklijke Bibliotheek (UKB), a consortium of Dutch university libraries and the National Library of the Netherlands. Other examples of our collective collections work, including a compendium of selected collective collection analyses from OCLC Research, are available online.
All of this is part of our work in the Understanding the System-wide Library research theme, where we explore issues having to do with library collections and services at scale. Collective collections are a key focus of this work, but we also look at how libraries make sourcing and scaling decisions in a networked environment, and how local collections are enhanced and amplified through resource sharing networks. The common theme: libraries looking above the institution to meet shared needs and create mutual value. Through collective collections, libraries are finding creative ways to do just that.
 For more on the North American collective print book collection, see Print Management at “Mega-scale”: A Regional Perspective on Print Book Collections in North America.
 Streib, K. 2016. “Collaboration: The Master Key to Unlocking Twenty-First Century Library Collections”, in Shared Collections, Collaborative Stewardship, D. Hale, editor. Chicago: ALA Editions. (p. 5)