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Demand-Driven Acquisitions (DDA) Pilot Project, 2015

During the 2014-15 academic year, the Trent University Library held a pilot project for "Demand-Driven Acquisitions" (DDA). This model of collection development allows library clients to select which books are purchased, by using the books.

Academic libraries small and large have instituted some form of DDA collection development practice over the last five years.  At Trent we've found that we're spending increasing amounts of time managing a decreasing budget in an equitable manner.  With the aim of exploring DDA as a component of collection development, the Library's Learning & Liaison Unit and Technical Services Unit developed this pilot project.

The Project

Over 16,000 e-book records were loaded into TOPCAT in January - March of 2015.

  • These were all recent, scholarly publications, from a variety of publishers in a wide range of subject areas. 
  • The titles were selected based on strict parameters established by the Library, and in partnership with a library service provider.
  • The Library did not actually own any of these books at this point, but they were fully catalogued and available for clients to find when searching TOPCAT. 
  • The TOPCAT record provided a direct link to the book on an e-book platform (either ebrary or EBSCO eBooks), where the client could view the book.

When someone actually used one of these e-books (where "use" was based on significant printing, viewing, or copying), it triggered a purchase of the book. At this point the Library paid for the book and it remained in TOPCAT and available through the e-book platform.  At the end of the pilot, all records for books that were not purchased were removed from TOPCAT.

Thus, only books that were actually used (for more than a brief glimpse) were purchased.  That's what makes it "demand-driven".


Uptake of the DDA e-books was very fast.  277 e-book purchases were triggered February 12 - April 2.  March was the busiest month, when about 50 titles per week were triggered for purchase. Here are some statistics.

Purchased titles by publisher:

  • 90 titles were from University presses - Cambridge, Yale, and Harvard,
  • 53 were from Taylor & Francis,
  • 47 were from Palgrave Macmillan,
  • 22 were from Ashgate.

Purchased titles by LC (call number) range:

  • B range: 28 titles
  • D range: 35 titles
  • E-F range: 10 titles
  • G range: 17 titles
  • H range: 82 titles
  • J-K range: 8 titles
  • L range: 15 titles
  • P range: 34 titles
  • Q range: 4 titles
  • R range: 33 titles
  • S-Z range: 11 titles


The funds allocated to the project were spent quickly, which might be explained by several factors.

  • The timing of the project was designed to coincide with the busiest time of year, after the February Reading Week.
  • TOPCAT always shows the most recently added items at the top of the results list, and these books were usually the newest items.
  • These books were all very current, making them attractive after relatively "dry" years of monograph acquisitions.
  • As e-books, they're more accessible and convenient to all types of users in any location. Library clients are clearly adopting this medium for scholarly monographs.

Issues with the project include:

  • When the money was spent, there were a few days when the records remained in TOPCAT but no purchase could be triggered.  This resulted in an error message if someone tried to access them.  Unfortunately, removing the un-purchased books took time, partially due to the limitations of our aging Library software.
  • These books were all purchased with a single-user license. The price of an e-book is determined by the publisher, and multi-user licenses are more expensive, often exceedingly so. When a single-user title is in use, an error message is shown to anyone else who tries to use it.
  • Because the books appeared in TOPCAT, and clients could not tell the difference between a book we already own and one that is purchased only when it's used, some titles that might otherwise have been purchased by departments might not have been.
  • Some titles were costly - over $120.  In future we might not include the more expensive publishers.

Future Implications

We're going to consider using DDA as a part of our ongoing collection development.  We're planning a reorganization of the entire Library acquisitions process, and patron-driven requests will play a large part, whether through DDA or a request system. 

We'll attempt to track ongoing use of the titles purchased through this pilot project, to see if they received significant use.

We recognize that a desire for print (hard-copy) books still exists, and they don't fit into this purchasing model.